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                              Handbook 139
                          Craters of the Moon


                     A Guide to Craters of the Moon
                           National Monument
                                 Idaho

                            Produced by the
                        Division of Publications
                         National Park Service

                    U.S. Department of the Interior
                         Washington, D.C. 1991

    [Illustration: {uncaptioned}]


                         _Using This Handbook_

Craters of the Moon National Monument protects volcanic features of the
Craters of the Moon lava field. Part 1 of this handbook introduces the
park and recounts its early exploration. Part 2 explores how life has
adapted to the park’s volcanic landscape—and how people have perceived
it. Part 3 presents concise travel guide and reference materials for
touring the park and for camping.

National Park Handbooks are published to support the National Park
Service’s management programs and to promote understanding and enjoyment
of the more than 350 National Park System sites, which represent
important examples of our country’s natural and cultural inheritance.
Each handbook is intended to be informative reading and a useful guide
before, during, and after a park visit. More than 100 titles are in
print. They are sold at parks and can be purchased by mail from the
Superintendent of Documents, U.S. Government Printing Office,
Washington, DC 20402. This is handbook number 139.


          _Library of Congress Cataloging-in-Publication Data_

Craters of the Moon: A Guide to Craters of the Moon National Monument,
Idaho/produced by the Division of Publications, National Park Service.


  p. cm.—(Official national park handbook; 139)
  1. Craters of the Moon National Monument (Idaho)—Guidebooks.
  2. Geology—Idaho—Craters of the Moon National Monument—Guidebooks.
    I. United States National Park Service. Division of Publications.
    II. Series: Handbook (United States. National Park Service. Division
          of Publications); 139.
  F752.C7C73    1991    917.96'59—dc20    89-13670CIP
  ISBN 0-912627-44-1


  Part 1 Welcome to Craters of the Moon                                 4
      Rift Volcanism on the Snake River Plain                           7
  Part 2 From Moonscape to Landscape                                   20
      Geology of the Craters of the Moon                               23
      Life Adapts to a Volcanic Landscape                              35
      Indians, Early Explorers, and Practicing Astronauts              47
  Part 3 Guide and Adviser                                             52
      Approaching Craters of the Moon                                  54
      Visitor Center and Programs                                      56
      Map                                                              58
      Take the Driving Tour                                            59
      Camping and Backcountry Use                                      60
      Winter Recreation                                                61
      Regulations and Safety                                           62
      Nearby Attractions                                               63
      Armchair Explorations                                            64




                                 Part 1
                     Welcome to Craters of the Moon


    [Illustration: {uncaptioned}]

    [Illustration: _Rock or rope? Folds of lava rock look like coils of
    irregular rope. Lava flows of this type are known as pahoehoe, a
    Hawaiian word pronounced_ pah-hoy-hoy _and meaning ropey_.]




                Rift Volcanism on the Snake River Plain


Light playing on cobalt blue lavas of the Blue Dragon Flows caught the
inner eye of explorer Robert Limbert: “It is the play of light at sunset
across this lava that charms the spectator. It becomes a twisted, wavy
sea. In the moonlight its glazed surface has a silvery sheen. With
changing conditions of light and air, it varies also, even while one
stands and watches. It is a place of color and silence....”

Limbert explored the Craters of the Moon lava field in Idaho in the
1920s and wrote those words for a 1924 issue of _National Geographic
Magazine_. “For several years I had listened to stories told by fur
trappers of the strange things they had seen while ranging in this
region,” wrote Limbert, a sometime taxidermist, tanner, and furrier from
Boise, Idaho. “Some of these accounts seemed beyond belief.” To Limbert
it seemed extraordinary “That a region of such size and scenic
peculiarity, in the heart of the great Northwest, could have remained
practically unknown and unexplored....” On his third and most ambitious
trek, in 1924, Limbert and W. C. Cole were at times left speechless by
the lava landscape they explored. Limbert recounted his impressions in
magazine and newspaper articles whose publication was influential in the
area’s being protected under federal ownership. In 1924, part of the
lava field was proclaimed as Craters of the Moon National Monument,
protected under the Antiquities Act. It was created “to preserve the
unusual and weird volcanic formations.” The boundary has been adjusted
and the park enlarged since then. In 1970, a large part of the national
monument was designated by Congress as the Craters of the Moon
Wilderness. It is further protected under the National Wilderness
Preservation System.

Until 1986, little was known about Limbert except for those facts
recounted above. That year, however, a researcher compiling a history of
the national monument located Limbert’s daughter in Boise. The daughter
still possessed hundreds of items, including early glass plate
negatives, photographs, and manuscripts of her father and that shed more
light on his life, the early days of Idaho, and Craters of the Moon.
Some of these photographs served as blueprints for the National Park
Service in the rehabilitation of fragile spatter cone formations that
have deteriorated over the years of heavy human traffic. The Limbert
collection has been fully cataloged by Boise State University curators
and has already proven to be a valuable resource to historians
interested in Limbert and this fascinating part of Idaho. Preservation
of the area owes much to Limbert’s imaginative advocacy in the true
spirit of the West in its earlier days.

Local legends, beginning in the late 1800s, held that this area
resembled the surface of the moon, on which—it must now be remembered—no
one had then walked! Geologist Harold T. Stearns first used the name
Craters of the Moon when he suggested to the National Park Service, in
1923, that a national monument be established here. Stearns found “the
dark craters and the cold lava, nearly destitute of vegetation” similar
to “the surface of the moon as seen through a telescope.” The name
Craters of the Moon would stick after Limbert adopted it in _National
Geographic Magazine_ in 1924. Later that year the name became official
when the area was set aside by President Calvin Coolidge as a national
monument under the Antiquities Act.

Like some other areas in the National Park System, Craters of the Moon
has lived to see the name that its early explorers affixed to it proved
somewhat erroneous by subsequent events or findings. When Stearns and
Limbert called this lava field Craters of the Moon, probably few persons
other than science fiction buffs actually thought that human beings
might one day walk on the moon and see firsthand what its surface is
like. People have now walked on the moon, however, and we know that its
surface does not, in fact, closely resemble this part of Idaho. Although
there are some volcanic features on the surface of the moon, most of its
craters were formed by the impact of meteorites colliding with the moon.

Moonscape or not, early fur trappers avoided the lava flows along the
base of the Pioneer Mountains at the north of today’s park. In doing so,
they followed Indian trails such as one found by Limbert that “resembled
a light streak winding through the lava. When the sun was directly
overhead it could be seen to advantage, but at times was difficult to
follow. Think of the years of travel,” Limbert marveled, “necessary to
make that mark on rock!” At least one Indian trail was destined to
become part of Goodale’s Cutoff, an alternative route on the Oregon
Trail that pioneers in wagon trains used in the 1850s and 1860s. Many
adjectives early used for this scene—weird, barren, exciting,
awe-inspiring, monotonous, astonishing, curious, bleak, mysterious—still
apply. It is not difficult today to see why pioneering folk intent on
wresting a living from the land did not tackle this volcanic terrain.

Geologists possessed the proper motivation to tackle it, however.
Curiosity aroused by this lava field has led several generations of
geologists, beginning with Israel C. Russell in 1901 and Harold T.
Stearns in the 1920s, into a deeper understanding of its volcanic
origins. With ever increasing penetration of its geological history, the
apparent otherworldliness of Craters of the Moon has retreated—but not
entirely. The National Aeronautics and Space Administration (NASA)
brought the second set of astronauts who would walk on the moon to this
alien corner of the galaxy before their moonshot. Here they studied the
volcanic rock and explored an unusual, harsh, and unforgiving
environment before embarking on their own otherworldly adventure.

Most types of volcanic features in the park can be seen quite readily by
first stopping at the visitor center and then driving the Loop Road. Far
more features can be seen if you also walk the interpretive trails at
the stops along the Loop Road. Still more await those who invest the
time required to come to feel the mysterious timelessness and raw
natural force implicit in this expansive lava field. Many travelers are
en route to Yellowstone National Park and spend only a couple of hours
visiting Craters of the Moon. This is ironic because here you are on the
geological track of Yellowstone. In fact, Craters of the Moon represents
what Yellowstone’s landscape will resemble in the future, and both areas
can supplement your insight into what happens when the Earth’s
unimaginable inner forces erupt to its surface.

    [Illustration: _Silvery leaves of the buckwheat dot a cinder garden
    with such regular spacing they almost look planted. Such spacing
    results from the shortage of available surface water: Each plant
    controls with its roots the space surrounding it, discouraging
    competing plants. Rainwater and snowmelt penetrate volcanic cinders
    so readily that their moisture quickly drops beyond reach of most
    plants’ root systems. For a close-up view of a buckwheat, see page
    36._]

Although Idaho is famous for forests, rivers, and scenic mountain
wilderness, its Snake River Plain region boasts little of these
attributes. This plain arcs across southern Idaho from the Oregon border
to the Yellowstone area at the Montana-Wyoming border. It marks the
trail of the passage of the Earth’s crust over an unusual geologic heat
source that now brings the Earth’s incendiary inner workings so close to
its surface near Yellowstone. This heat source fuels Yellowstone’s
bubbling, spewing, spouting geothermal wonders. Craters of the Moon
therefore stands as a geologic prelude to Yellowstone, as its precursor
and the ancestral stuff of its fiery secrets.

When did all this volcanism at Craters of the Moon happen? Will it
happen again? According to Mel Kuntz and other U.S. Geological Survey
geologists who have conducted extensive field research at Craters of the
Moon, the volcanic activity forming the Craters of the Moon lava field
probably started _only_ 15,000 years ago. The last eruption in the
volcanic cycle ended 2,000 years ago, about the time that Julius Caesar
ruled the Roman Empire.

Craters of the Moon is a dormant, but not extinct, volcanic area. Its
sleeping volcanoes could become active again in the near future. The
largest earthquake of the last quarter century in the contiguous United
States shook Idaho’s tallest mountain, Borah Peak, just north of here in
1983. When it did, some geologists wondered if it might initiate
volcanic activity at Craters of the Moon. It did not. According to
Kuntz, however, this is no reason not to expect another volcanic
eruption here _soon_—probably “within the next 1,000 years.” Part Two of
this handbook explores the still young and rapidly evolving
understanding of the fascinating geologic story of Craters of the Moon.

Today’s Craters of the Moon National Monument encompasses 83 square
miles of the much larger Craters of the Moon lava field. Reaching
southeastward from the Pioneer Mountains, the park boundary encloses a
series of fissure vents, volcanic cones, and lava flows known as the
Great Rift volcanic zone. This volcanic rift zone is a line of weakness
in the Earth’s crust that can be traced for some 60 miles across the
Snake River Plain. Recent volcanism marks much of its length. You can
explore the Great Rift and some of its volcanic features via the park’s
7-mile Loop Drive, as described in Part Three of this handbook. In the
park’s northern part you will find spatter cones, cinder cones, lava
flows, lava caves, and an unexpected variety of wildflowers, shrubs,
trees, and wild animals. The much larger southern part of the park,
designated by Congress in 1970 as the Craters of the Moon Wilderness
Area, is a vast and largely untraveled region of stark volcanic features
flanking the Great Rift. It offers a challenge to serious hikers and
explorers—latter day Robert Limberts—who are prepared for rugged
wilderness travel.

Despite its seeming barrenness, Craters of the Moon is indeed home to a
surprising diversity of plant and animal life. As Limbert noted in 1924:
“In the West the term ‘Lava Beds of Idaho’ has always signified a region
to be shunned by even the most venturesome travelers—a land supposedly
barren of vegetation, destitute of water, devoid of animal life, and
lacking in scenic interest.

“In reality the region has slight resemblance to its imagined aspect.
Its vegetation is mostly hidden in pockets, but when found consists of
pines, cedars, junipers, and sagebrush: its water is hidden deep in
tanks or holes at the bottom of large ‘blow-outs’ and is found only by
following old Indian or mountain sheep trails or by watching the flight
of birds as they drop into these places to quench their thirst. The
animal life consists principally of migrant birds, rock rabbits,
woodchucks, black and grizzly bears: its scenery is impressive in its
grandeur.”

Years of patient record-keeping by scientists have fit numbers to
Limbert’s perceptive observations. The number of species identified
includes more than 300 plants, 2,000 insects, 8 reptiles, 140 birds, 30
mammals—and one amphibian, the western toad. We now call Limbert’s “rock
rabbit” the pika. The grizzly is long gone here. With few exceptions,
the park’s denizens live mostly under conditions of great environmental
stress.

Near constant winds, breeze-to-gale in strength, sweep across the park
to rob moisture from all living things. Scant soils, low levels of
precipitation, the inability of cinder cones to hold rainwater near the
surface, and the heat of the summer sun—intensified by heat-absorbing
black lavas—only aggravate such moisture theft. Cinder surfaces register
summer soil temperatures of over 150°F and show a lack of plant cover.
Plants cover generally less than 5 percent of the total surface of the
cinder cones. A recent study found that when the area is looked at on a
parkwide basis, most of the land is very sparsely vegetated (less than
15 percent vegetative cover). On a scale of sand trap to putting green,
this would approach the sand trap end of the scale.

    [Illustration: _Winter snow transforms these landscapes, smoothing
    out both contours and the jagged edges of lavas. Less lunar in
    appearance now, the park nonetheless maintains an otherworldly
    aura._]

    [Illustration: _The park was named in 1924, 45 years before humans
    walked on the Moon. Although we now know more about the Moon’s
    actual surface, the park’s name still rings true. Only a few trees
    immediately suggest that the large photo was taken on Earth. In the
    inset photo, astronaut Edwin E. “Buzz” Aldrin walks on the Moon near
    the lunar module._]

Into this difficult environment wildlife researcher Brad Griffith
ventured to count, mark, and scrutinize the mule deer of Craters of the
Moon in May 1980. Griffith, of the University of Idaho, conducted a
three-year study of the park’s mule deer population because the National
Park Service was concerned that this protected and productive herd might
multiply so much that it would eventually damage its habitat. Among
other things, he would find that the herd has developed a drought
evasion strategy that makes it behave unlike any mule deer population
known anywhere else.

“By late summer,” Griffith explains, “plants have matured and dried so
that they no longer provide adequate moisture to sustain the deer in
this landscape that offers them no free water. Following about 12 days
of warm nights and hot days in late July, the deer migrate from 5 to 10
miles north to the Pioneer Mountains. There they find free-flowing
creeks and the cool, moist shade of aspen and Douglas-fir groves and
wait out summer’s worst heat and dryness. Early fall rains trigger the
deer’s return to the park’s wilderness from this oasis in late September
to feed on the nutritious bitterbrush until November snowfalls usher
them back to their winter range.”

The pristine and high-quality forage of the Craters of the Moon
Wilderness Area, historically nearly untouched by domestic livestock
grazing, has inspired this migratory strategy for evading drought. In
effect, the mule deer make use of a dual summer range, a behavioral
modification unknown elsewhere for their species.

“Their late summer and fall adaptations simply complete the mule deer’s
yearlong strategy for coping with the limits that this volcanic
landscape imposes on them,” Griffith explains.

Taking a walk in the park on a mid-summer afternoon gives you a good
opportunity to experience the influence of wind, heat, and lack of
moisture. The park’s winds are particularly striking. The lava that has
flowed out of the Great Rift has built up and raised the land surface in
the park to a higher elevation than its surroundings so that it
intercepts the prevailing southwesterly winds. Afternoon winds usually
die down in the evening. As part of the dynamics of temperature and
moisture that determine mule deer behavior, this daily wind cycle helps
explain why they are more active at night than are mule deer elsewhere.
These deer do not move around as much as mule deer in less ecologically
trying areas. They have adapted behaviors to conserve energy and
moisture in this environmentally stressful landscape.

Early mornings may find park rangers climbing up a cinder cone to count
the deer, continuing the collection of data that Brad Griffith set in
motion with his three-year study. The rangers still conduct spring and
late summer censuses: over a recent three-year period the deer
populations averaged about 420 animals. Another several years of
collecting will give the National Park Service a body of data on the
mule deer that is available nowhere else.

The uniqueness of this data about the park’s mule deer population would
surely please the booster aspect of Robert Limbert’s personality.
Likewise, the research challenges involved in obtaining it would appeal
to his explorer self. History has justified Limbert on both counts.
Publicity arising from his explorations led to creation of the national
monument. Furthermore, that publicity put forth a rather heady claim
that history has also unequivocally borne out: “Although almost totally
unknown at present,” Limbert prophesied in 1924, “this section is
destined some day to attract tourists from all America....”

Every year tens of thousands of travelers fulfill Robert Limbert’s
prophecy of more than a half-century ago.




                                 Part 2
                      From Moonscape to Landscape


    [Illustration: {uncaptioned}]

    [Illustration: _What last happened here about 2,000 years ago looked
    much like this photograph of a volcanic eruption in Hawaii.
    Bubbling, pooling, and flowing lava blanketed the landscape as
    molten materials poured or gushed out of the Earth. Most volcanic
    phenomena preserved at Craters of the Moon have been seen in action
    in Hawaii._]




                   Geology of the Craters of the Moon


A 400-mile-long arc known as the Snake River Plain cuts a swath from 30
to 125 miles wide across southern Idaho. Idaho’s official state highway
map, which depicts mountains with shades of green, shows this arc as
white because there is comparatively little variation here compared to
most of the state. Upon this plain, immense amounts of lava from within
the Earth have been deposited by volcanic activity dating back more than
14 million years. However, some of these lavas, notably those at Craters
of the Moon National Monument, emerged from the Earth as recently as
2,000 years ago. Craters of the Moon contains some of the best examples
of basaltic volcanism in the world. To understand what happened here,
you must understand the Snake River Plain.

Basaltic and Rhyolitic Lavas. The lavas deposited on the Snake River
Plain were mainly of two types classified as basaltic and rhyolitic.
Magma, the molten rock material beneath the surface of the Earth, issues
from a volcano as lava. The composition of this fluid rock material
varies. Basaltic lavas are composed of magma originating at the boundary
of the Earth’s mantle and its crustal layer. Rhyolitic lavas originate
from crustal material. To explain its past, geologists now divide the
Snake River Plain into eastern and western units. The following geologic
story relates to the eastern Snake River Plain, on which Craters of the
Moon lies.

On the eastern Snake River Plain, basaltic and rhyolitic lavas formed in
two different stages of volcanic activity. Younger basaltic lavas mostly
lie atop older rhyolitic lavas. This portion of the plain runs from
north of Twin Falls eastward to the Yellowstone area on the
Wyoming-Montana border. Drilling to depths of almost 2 miles near the
plain’s midline, geologists found ½ mile of basaltic lava flows lying
atop more than 1½ miles of rhyolitic lava flows. How much deeper the
rhyolitic lavas may extend is not known. No one has drilled deeper here.

    [Illustration: _Crossing Idaho in an arc, the Snake River Plain
    marks the path of the Earth’s crustal plate as it migrates over a
    heat source unusually close to the surface. It is believed that the
    heat source fueling Yellowstone’s thermal features today is
    essentially the same one that produced volcanic episodes at Craters
    of the Moon ending about 2,000 years ago._]

This combination—a thinner layer of younger basaltic lavas lying atop an
older and thicker layer of rhyolitic lavas—is typical of volcanic
activity associated with an unusual heat phenomenon inside the Earth
that some geologists have described as a mantle plume. The mantle plume
theory was developed in the early 1970s as an explanation for the
creation of the Hawaiian Islands. According to the theory, uneven
heating within the Earth’s core allows some material in the overlying
mantle to become slightly hotter than surrounding material. As its
temperature increases, its density decreases. Thus it becomes relatively
buoyant and rises through the cooler materials—like a tennis ball
released underwater—toward the Earth’s crust. When this molten material
reaches the crust it eventually melts and pushes itself through the
crust and it erupts onto the Earth’s surface as molten lava.

The Earth’s crust is made up of numerous plates that float upon an
underlying mantle layer. Therefore, over time, the presence of an
unusual heat source created by a mantle plume will be expressed at the
Earth’s surface—floating in a constant direction above it—as a line of
volcanic eruptions. The Snake River Plain records the progress of the
North American crustal plate—350 miles in 15 million years—over a heat
source now located below Yellowstone. The Hawaiian chain of islands
marks a similar line. Because the mechanisms that cause this geologic
action are not well understood, many geologists refer to this simply as
a heat source rather than a mantle plume.

Two Stages of Volcanism. As described above, volcanic eruptions
associated with this heat source occur in two stages, rhyolitic and
basaltic. As the upwelling magma from the mantle collects in a chamber
as it enters the Earth’s lower crust, its heat begins to melt the
surrounding crustal rock. Since this rock contains a large amount of
silica, it forms a thick and pasty rhyolitic magma. Rhyolitic magma is
lighter than the overlying crustal rocks, therefore, it begins to rise
and form a second magma chamber very close to the Earth’s surface. As
more and more of this gas-charged rhyolitic magma collects in this upper
crustal chamber, the gas pressure builds to a point at which the magma
explodes through the Earth’s crust.

Explosive Rhyolitic Volcanism. Rhyolitic explosions tend to be
devastating. When the gas-charged molten material reaches the surface of
the Earth, the gas expands rapidly, perhaps as much as 25 to 75 times by
volume. The reaction is similar to the bubbles that form in a bottle of
soda pop that has been shaken. You can shake the container and the
pressure-bottled liquid will retain its volume as long as the cap is
tightly sealed. Release the pressure by removing the bottle cap,
however, and the soft drink will spray all over the room and occupy a
volume of space far larger than the bottle from which it issued. This
initial vast spray is then followed by a foaming action as the less
gas-charged liquid now bubbles out of the bottle.

Collectively, the numerous rhyolitic explosions that occurred on the
Snake River Plain ejected hundreds of cubic miles of material into the
atmosphere and onto the Earth’s surface. In contrast, the eruption of
Mount Saint Helens in 1980, which killed 65 people and devastated 150
square miles of forest, produced less than 1 cubic mile of ejected
material. So much material was ejected in the massive rhyolitic
explosions in the Snake River Plain that the Earth’s surface collapsed
to form huge depressions known as calderas. (Like _caldron_, whose root
meaning it shares, this name implies both bowl-shaped and warmed.) Most
evidence of these gigantic explosive volcanoes in the Snake River Plain
has been covered by subsequent flows of basaltic lava. However, traces
of rhyolitic eruptions are found along the margins of the plain and in
the Yellowstone area.

Quiet Outpourings of Basaltic Lava. As this area of the Earth’s crust
passed over and then beyond the sub-surface heat source, the explosive
volcanism of the rhyolitic stage ceased. The heat contained in the
Earth’s upper mantle and crust, however, remained and continued to
produce upwelling magma. This was basaltic magma that, because it
contained less silica than rhyolite, was very fluid.

The basalt, like the rhyolite, collected in isolated magma chambers
within the crust until pressures built up to force it to the surface
through various cracks and fissures. These weak spots in the Earth’s
crust were the results of earlier geologic activity, expansion of the
magma chamber, or the formation of a rift zone.

    [Illustration: _Microscopic cross section of basaltic rock._]

    [Illustration: _Microscopic cross section of rhyolitic rock. Cross
    sections show vastly different textures. Rhyolitic magma contains
    more silica; it is very thick and does not allow trapped gas to
    escape easily. Its volcanic eruptions blast large craters in the
    Earth’s crust. Basaltic magma is more fluid and allows gas to escape
    readily. It erupts more gently. Here in the eastern Snake River
    Plain, basaltic lava flows almost completely cover earlier rhyolitic
    deposits._]

(_continued on page 28_)


                       Identifying the Lava Flows

  At Craters of the Moon the black rocks are lava flows. The surface
  lava rocks, basaltic in composition, formed from magma originating
  deep in the Earth. They are named for their appearances: Pahoehoe
  (pronounced “pah-hoy-hoy” and meaning “ropey”), Aa (pronounced “ah-ah”
  and meaning “rough”), or Blocky. Geologists have seen how these flows
  behave in modern volcanic episodes in Hawaii and elsewhere.

    [Illustration: _Pahoehoe lava_]

  Pahoehoe More than half the park is covered by pahoehoe lava flows.
  Rivers of molten rock, they harden quickly to a relatively smooth
  surface, billowly, hummocky, or flat. Other pahoehoe formations
  resemble coiled, heavy rope or ice jams.

    [Illustration: _Aa lava_]

  Aa Aa flows are far more rugged than pahoehoe flows. Most occur when a
  pahoehoe flow cools, thickens, and then turns into aa. Often
  impassable to those traveling afoot, aa flows quickly chew up hiking
  boots. Blocky lava is a variety of aa lava whose relatively large
  silica content makes it thick and often dense, glassy, and smooth.

    [Illustration: _Blocky lava_]

  Bombs Lava pieces blown out of craters may solidify in flight. They
  are classed by shape: spindle, ribbon, and breadcrust. Bombs range
  from ½ inch to more than 3 feet long.

  Tree Molds When molten lava advances on a living forest, resulting
  tree molds may record impressions of charred surfaces of trees in the
  lava.

    [Illustration: _Blue Dragon Flows lava_]

    [Illustration: _Breadcrust bomb_]

    [Illustration: _Spindle bomb_]

    [Illustration: _Wood-like lava_]

    [Illustration: _Tree mold_]

    [Illustration: _Lava river_]

    [Illustration: _Mt. St. Helens erupts in 1980. Because the lava
    contained a large amount of silica, its explosive eruption contrasts
    sharply with recent basaltic flows in volcanic activity in Hawaii._]

    [Illustration: Basaltic flows in Hawaii.]

Upon reaching the surface, the gases contained within the lava easily
escaped and produced rather mild eruptions. Instead of exploding into
the air like earlier rhyolitic activity, the more fluid basaltic lava
flooded out onto the surrounding landscape. These flows were fairly
extensive and often covered many square miles. After millions of years,
most of the older rhyolitic deposits have been covered by these basaltic
lava flows.

The Great Rift and Craters of the Moon. Craters of the Moon National
Monument lies along a volcanic rift zone. Rift zones occur where the
Earth’s crust is being pulled in opposite directions. Geologists believe
that the interactions of the Earth’s crustal plates in the vicinity of
the Snake River Plain have stretched, thinned, and weakened the Earth’s
crust so that cracks have formed both on and below the surface here.
Magma under pressure can follow these cracks and fissures to the
surface. While there are many volcanic rift zones throughout the Snake
River Plain, the most extensive is the Great Rift that runs through
Craters of the Moon. The Great Rift is approximately 60 miles long and
it ranges in width from 1½ to 5 miles. It is marked by short cracks—less
than 1 mile in length—and the alignment of more than 25 volcanic cinder
cones. It is the site of origin for more than 60 different lava flows
that make up the Craters of the Moon Lava Field.

Eight Major Eruptive Periods. Most of the lavas exposed at Craters of
the Moon formed between 2,000 and 15,000 years ago in basaltic eruptions
that comprise the second stage of volcanism associated with the mantle
plume theory. These eight eruptive periods each lasted about 1,000 years
or less and were separated by periods of relative calm that lasted for a
few hundred to more than 2,000 years. These sequences of eruptions and
calm periods are caused by the alternating build up and release of
magmatic pressure inside the Earth. Once an eruption releases this
pressure, time is required for it to build up again.

Eruptions have been dated by two methods: paleomagnetic and radiocarbon
dating. Paleomagnetic dating compares the alignment of magnetic minerals
within the rock of flows with past orientations of the Earth’s magnetic
fields. Radiocarbon dating makes use of radioactive carbon-14 in
charcoal created from vegetation that is overrun by lava flows. Dates
obtained by both methods are considered to be accurate to within about
100 years.

A Typical Eruption at Craters of the Moon. Research at the monument and
observations of similar eruptions in Hawaii and Iceland suggest the
following scenario for a typical eruption at Craters of the Moon.
Various forces combine to cause a section of the Great Rift to pull
apart. When the forces that tend to pull the Earth’s crust apart are
combined with the forces created as magma accumulates, the crust becomes
weakened and cracks form. As the magma rises buoyantly within these
cracks, the pressure exerted on it is reduced and the gases within the
magma begin to expand. As gas continues to expand, the magma becomes
frothy.

At first the lava is very fluid and charged with gas. Eruptions begin as
a long line of fountains that reach heights of 1,000 feet or less and
are up to a mile in length. This “curtain of fire eruption” mainly
produces cinders and frothy, fluid lava. After hours or days, the
expansion of gases decreases and eruptions become less violent. Segments
of the fissure seal off and eruptions become smaller and more localized.
Cinders thrown up in the air now build piles around individual vents and
form cinder cones.

With further reductions in the gas content of the magma, the volcanic
activity again changes. Huge outpourings of lava are pumped out of the
various fissures or the vents of cinder cones and form lava flows. Lava
flows may form over periods of months or possibly a few years. Long-term
eruptions of lava flows from a single vent become the source of most of
the material produced during a sustained eruption. As gas pressure falls
and magma is depleted, flows subside. Finally, all activity stops.

When Will the Next Eruption Occur? Craters of the Moon is not an extinct
volcanic area. It is merely in a dormant stage of its eruptive sequence.
By dating the lava flow, geologists have shown that the volcanic
activity along the Great Rift has been persistent over the last 15,000
years, occurring approximately every 2,000 years. Because the last
eruptions took place about 2,000 years ago, geologists believe that
eruptions are due here again—probably within the next 1,000 years.

    [Illustration: _From the air the Great Rift looks like an
    irregularly dashed line punctuated by tell-tale cones and craters._]

    [Illustration: _Chainlike, the Hawaiian group of islands traces the
    migration of Earth’s crustal plate over an unusual undersea heat
    source. The Hawaiian chain of islands and the Snake River Plain map
    similar happenings._]

(_continued on page 34_)


                             Indian Tunnel

    [Illustration: {uncaptioned}]

  Indian Tunnel looks like a cave, but it is a lava tube. When a
  pahoehoe lava flow is exposed to the air, its surface begins to cool
  and harden. A crust or skin develops. As the flow moves away from its
  source, the crust thickens and forms an insulating barrier between
  cool air and molten material in the flow’s interior. A rigid roof now
  exists over the stream of lava whose molten core moves forward at a
  steady pace. As the flow of lava from the source vent is depleted, the
  level of lava within the molten core gradually begins to drop. The
  flowing interior then pulls away from the hardening roof above and
  slowly drains away and out. The roof and last remnants of the lava
  river inside it cool and harden, leaving a tube.

    [Illustration: _Lava tube_]

    [Illustration: _Great horned owl_]

  Many lava tubes make up the Indian Tunnel Lava Tube System. These
  tubes formed during the same eruption within a single lava flow whose
  source was a fissure or crack in the Big Craters/Spatter Cones area. A
  tremendous amount of lava was pumped out here, forming the Blue Dragon
  Flows. (Hundreds of tiny crystals on its surface produce the color
  blue when light strikes them.) Lava forced through the roof of the
  tube system formed huge ponds whose surfaces cooled and began to
  harden. Later these ponds collapsed as lava drained back into the lava
  tubes. Big Sink is the largest of these collapses. Blue Dragon Flows
  cover an area of more than 100 square miles. Hidden beneath are miles
  of lava tubes, but collapsed roof sections called skylights provide
  entry to only a small part of the system. Only time, with the collapse
  of more roofs, will reveal the total extent of the system.

    [Illustration: _Icicles (ice stalactites)_]

    [Illustration: _Lava stalactites_]

  Stalactites Dripped from hot ceilings, lava forms stalactites that
  hang from above. Mineral deposits Sulfate compounds formed on many
  lava tube ceilings from volcanic gases or by evaporation of matter
  leached from rocks above. Ice In spring, ice stalactites form on cave
  ceilings and walls. Ice stalagmites form on the cave floor. Summer
  heat destroys these features. Wildlife Lava tube beetles, bushy-tailed
  woodrats (packrats), and bats live in some dark caves. Violet-green
  swallows, great horned owls, and ravens may use wall cracks and
  shelves of well-lit caves for nesting sites.


                     Cinder Cones and Spatter Cones

    [Illustration: {uncaptioned}]

    [Illustration: _Cinder cone_]

    [Illustration: _Spatter cone_]

  Cinder Cones When volcanic eruptions of fairly moderate strength throw
  cinders into the air, cinder cones may be built up. These cone-shaped
  hills are usually truncated, looking as though their tops were sliced
  off. Usually, a bowl- or funnel-shaped crater will form inside the
  cone. Cinders, which cooled rapidly while falling through the air, are
  highly porous with gas vesicles, like bubbles. Cinder cones hundreds
  of feet high may be built in a few days. Big Cinder Butte is a cinder
  cone. At 700 feet high it is the tallest cone in the park. The shape
  develops because the largest fragments, and in fact most of the
  fragments, fall closest to the vent. The angle of slope is usually
  about 30 degrees. Some cinder cones, such as North Crater, the
  Watchman, and Sheep Trail Butte, were built by more than one eruptive
  episode. Younger lava was added to them as a vent was rejuvenated. If
  strong winds prevailed during a cinder cone’s formation, the cone may
  be elongated—in the direction the wind was blowing—rather than
  circular. Grassy, Paisley, Sunset, and Inferno Cones are elongated to
  the east because the dominant winds in this area come from the west.
  The northernmost section of the Great Rift contains the most cinder
  cones for three reasons: 1. There were more eruptions at that end of
  the rift. 2. The lavas erupted there were thicker, resulting in more
  explosive eruptions. (They are more viscous because they contain more
  silica.) 3. Large amounts of groundwater may have been present at the
  northern boundary of the lavas and when it came in contact with magma
  it generated huge amounts of steam. All of these conditions lead to
  more extensive and more explosive eruptions that tend to create cinder
  cones rather than lava flows.

  Spatter Cones When most of its gas content has dissipated, lava
  becomes less frothy and more tacky. Then it is tossed out of the vent
  as globs or clots of lava paste called spatter. The clots partially
  weld together to build up spatter cones. Spatter cones are typically
  much smaller than cinder cones, but they may have steeper sides. The
  Spatter Cones area of the park (Stop 5 on the map of the Loop Drive)
  contains one of the most perfect spatter-cone chains in the world.
  These cones are all less than 50 feet high and less than 100 feet in
  diameter.

    [Illustration: _Lichens often pioneer new life on Earth. Two plants
    in one, lichens are composed of an alga and a fungus growing
    together to their mutual benefit, usually on rock. Hardy and
    slow-growing, lichens help break down rock to soil-building mineral
    matter._

    _Eventually their vegetable matter decays, helping to form the first
    soils that other plants can then use. Tough in the extreme, some
    lichens can be heated to high temperatures and still be capable of
    resuming normal growth when returned to viable conditions._]




                  Life Adapts to a Volcanic Landscape


Two thousand years after volcanic eruptions subsided, plants and animals
still struggle to gain toeholds on this unforgiving lava field. Much of
the world’s vegetation could not survive here at all. Environmental
stresses created by scant soil and minimal moisture are compounded by
highly porous cinders that are incapable of holding water near the
ground surface where plants and other organisms can make ready use of
it. Scarce at best—total average precipitation is between 15 to 20
inches per year—rainwater and snowmelt quickly slip down out of reach of
the plants growing on cinder cones. Summer’s hot, dry winds rob moisture
from all living things exposed to them. Whisking across leaves and
needles the winds carry away moisture precious to plant tissues. On the
side of a cinder cone, summer day temperatures at ground level can be
more than 150°F.

The secret to survival here is adaptation. Most life forms cope by
strategies of either resisting or evading the extremes of this semi-arid
climate. To resist being robbed of moisture by winds and heat, a plant
may feature very small leaves that minimize moisture loss. To evade
heat, wind, and aridity, another plant may grow inside a crevice that
provides life-giving shade and collects precious moisture and soil
particles. Another plant may spend about 95 percent of the year dormant.
It may rush through the germination, sprouting, leafing out, blooming,
and fruiting stages and return to the dormancy of its seed stage in just
two weeks. The dwarf buckwheat has adapted to life on porous cinders by
evolving a root system that may spread out for up to 3 feet to support
its aboveground part, which is a mere 4 inches high. This buckwheat only
looks like a dwarf because you can not see its roots.

                                                  (_continued on page 40_)


                  Plants Adapt to a Volcanic Landscape

    [Illustration: {uncaptioned}]

  Water is the limiting factor in plant growth and reproduction both on
  the lava fields of Craters of the Moon and on the surrounding
  sagebrush steppe. Plants have developed a combination of adaptations
  to cope with drought conditions. There are three major strategies:

  1. Drought tolerance Physiological adaptations leading to drought
  tolerance are typical of desert plant species. The tissues of some
  plants can withstand extreme dehydration without suffering permanent
  cell damage. Some plants can extract water from very dry soils.
  Sagebrush and antelope bitterbrush exemplify drought tolerance.

    [Illustration: _Dwarf monkeyflower_]

    [Illustration: _Buckwheat_]

  2. Drought avoidance Certain structural modifications can enable
  plants to retain or conserve water. Common adaptations of this type
  include small leaves, hairiness, and succulence. The small leaves of
  the antelope bitterbrush expose less area to evaporative influences
  such as heat and wind. Hairs on the scorpionweed reduce surface
  evaporation by inhibiting air flow and reflecting sunlight. Succulent
  plants such as pricklypear cactus have tissues that can store water
  for use during drought periods. Other plants, such as wire lettuce,
  avoid drought by having very little leaf surface compared to their
  overall volume.

  3. Drought escape  Some plants, such as mosses and ferns, escape
  drought by growing near persistent water supplies such as natural
  potholes and seeps from ice caves. Many other drought escapers, such
  as dwarf monkeyflower, simply carry out their full life cycle during
  the moist time of the year. The rest of the year they survive in seed
  form.

    [Illustration: _Pricklypear cactus_]

    [Illustration: _Ferns_]


                          Plant Microhabitats

    [Illustration: {uncaptioned}]

  Lava flows Most plants cannot grow on lava flows until enough soil has
  accumulated to support them. The park’s older volcanic landscapes,
  where soils are best developed, are clothed with sagebrush-grassland
  vegetation. On younger lava flows, bits of soil first accumulate in
  cracks, joints, and crevices. It is in these microhabitats that
  vascular plants may gain footholds. Narrow cracks and joints may
  contain desert parsley and lava phlox. Shallow crevices will hold
  scabland penstemon, fernleaf fleabane, and gland cinquefoil. Deep
  crevices can support the syringa, various ferns, bush rockspirea,
  tansybush, and even limber pine. Not until full soil cover is achieved
  can the antelope bitterbrush, rubber rabbitbrush, and sagebrush find
  suitable niches. On lava flows soils first form from eroded lava and
  the slow decomposition of lichens and other plants able to colonize
  bare rock. These soils can be supplemented by wind-blown soil
  particles until vascular plants gain footholds. As plants begin to
  grow and then die, their gradual decomposition adds further soil
  matter. These soil beginnings accumulate in cracks and crevices, which
  also provide critical shade and wind protection. Deep crevices provide
  lower temperatures favoring plant survival.

    [Illustration: _Rubber rabbitbrush_]

    [Illustration: _Syringa_]

  Cinder gardens Compared to the lava flows, cinder cones are much more
  quickly invaded by plants. Here, too, however, volcanic origins
  influence plant growth. Compared to the relatively level lava flows,
  steeply sloping cinder cones introduce a new factor that controls the
  development of plant communities: topography. Here you find marked
  differences in the plant communities between the north- and
  south-facing slopes. South-facing slopes are exposed to prolonged,
  intense sunlight, resulting in high evaporation of water. Because of
  the prevailing winds, snow accumulates on northeast sides of cones,
  giving them far more annual water than southwest-facing sides receive.
  The pioneering herbs that first colonize cinder cones will persist on
  southwest-facing slopes long after succeeding plant communities have
  come to dominate north-facing slopes. It is on these north-facing
  slopes that limber pine first develops in the cinder garden.
  South-facing slopes may never support the limber pine but may be
  dominated by shrubs. Unweathered cinder particles range in size from 3
  to 4 inches in diameter down to very small particles. They average
  about ¼ inch in diameter.

    [Illustration: _Cinquefoil_]

    [Illustration: _Wire lettuce_]

Ecological conditions at Craters of the Moon are generally so harsh that
slight changes can make the difference for the survival of a plant or
other organism. Life thrives in many rock crevices that are surrounded
by barren exposed lava rock of the same physical composition. These
microhabitats provide the critical shade and increased soil and moisture
content required for plant survival. Over the years, particles of soil
will naturally collect in rock crevices, which also have the effect of
funneling precipitation into their depths. Their shade further protects
these pockets of soil and water from wind erosion, excessive heat, and
evaporation and leaching by direct sunlight.

    [Illustration: _Limber pines are the tree pioneers of the lava
    terrain. Their seedlings often find suitable conditions for
    germination in rock crevices long before surrounding landscapes
    support tree growth. Most common of all the park’s trees, limber
    pine is named for its flexible branches. Many park animals depend on
    this tree in some fashion for their livelihoods._]

    [Illustration: _Limber pine cones stay green and resinous through
    their first year of development and then turn brown and woody as
    their seeds mature in the second year. Cones grow to about 4 inches
    long._]

At Craters of the Moon, crevices are of such importance to plants that
botanists differentiate between narrow, shallow, and deep crevices when
studying this phenomenon. Narrow crevices will support dwarf goldenweed
or hairy goldaster. Shallow crevices support scabland penstemon,
fernleaf fleabane, and gland cinquefoil. Deep crevices give rise to
syringa, ferns, bush rockspirea, tansybush, Lewis mockorange, and even
the limber pine tree. Complete soil cover and then vegetative cover can
develop on these lava flows only after crevices have first become filled
with soil.

Plants exploit other means of protection to survive in this harsh
environment. Shaded and wind-sheltered, the northern side of a cinder
cone can support grass, shrubs, and limber pine trees while the cone’s
southern face supports only scattered herbs. Most cinder cones in the
park show distinct differences of plant cover between their northern and
southern exposures. Northern exposures are cooler and more moist than
southern exposures, which receive far more direct sunlight. In addition,
here at Craters of the Moon, the prevailing southwesterly winds compound
the ability of the dry heat to rob porous cinder cone surfaces and their
living organisms of precious moisture.

The build-up of successive lava flows has so raised the landscape that
it now intercepts wind currents that operate higher above surrounding
plains. Limber pine trees find footholds on the shaded and sheltered
northern exposures of cinder cones. Bitterbrush and rabbitbrush shrubs
that can barely survive on the lower skirts of a cinder cone’s southern
side may grow two-thirds of the way up its protected northern face. For
many species of plants the limits of habitability on this volcanic
landscape are narrowly defined. Very small variations in their
situations can determine success or failure.

Travelers often ask park rangers whether or not some of the park’s
plants were planted by people. The plants in question are dwarf
buckwheats and grow in cinder gardens. It is their incredibly even
spacing that creates an orderliness that is easy to mistake for human
design. The regular spacing comes about because of the competition for
moisture, however. The root systems of these plants exploit the
available water from an area of ground surface much larger than the
spread of their foliage. In this way, mature plants can fend off
competition by using the moisture that would be required for a
potentially encroaching plant to become established. The effect is an
even spacing that makes it appear, indeed, as though someone had set out
the plants on measured centers.

Craters of the Moon abounds with these surprising plant microhabitats
that delight explorers on foot. The bleak lava flows separate these
emerging pockets of new life, isolating them like islands or oases
within their barren volcanic surroundings.

Scientists have studied Carey Kipuka, an island of plantlife in the most
southern part of the park, to find out what changes have occurred in the
biologic community. _Kipuka_ is a Hawaiian name given to an area of
older land that is surrounded by younger lava flows. Recent lava flows
did not overrun Carey Kipuka, so its plant cover is unaltered. Shortage
of water protected it from livestock grazing that might have changed its
character. Its vegetation is a benchmark for comparing plant cover
changes on similar sites throughout southern Idaho.

For the National Park Service and other managers of wildlands,
kipukas—representing isolated and pristine plant habitat unchanged by
human influence—provide the best answer that we have to the important
question, “What is natural?” Armed with a satisfactory answer to that
question, it is possible to manage the land ecologically. Park managers
can seek to restore natural systems and to allow them to be as
self-regulating as possible. It is ironic that Craters of the Moon, a
volcanic landscape subjected to profound change, should also protect
this informative glimpse of what remains unchanged.

    [Illustration: _From the park’s mazes of jumbled rock, ground
    squirrels fashion homes with many entrances and exits. Opportunistic
    feeders on vegetable matter, these engaging rodents fall prey to
    hawks and owls from above and small predatory mammals on the ground.
    They therefore serve as an important transfer point between plant
    and animal layers of the park’s food energy scheme._]

    [Illustration: _In the 1920s, members of the Limbert Expedition,
    described on pages 50 and 51, followed the flight of doves to locate
    water as they explored what later became the park._]

(_continued on page 46_)


                              Wildflowers

  Wildflowers carpet Craters of the Moon’s seemingly barren lava fields
  from early May to late September. The most spectacular shows of
  wildflowers come with periods of precipitation. In late spring,
  moisture from snowmelt—supplemented now and then by rainfall—sees the
  blossoming of most of the delicate annual plants.

  Many of the park’s flowering plants, having no mechanisms for
  conserving moisture, simply complete their life cycles before the
  middle of summer. This is particularly true of those that grow on the
  porous cinder gardens into which moisture quickly descends beyond
  reach of most plants’ root systems.

  As summer continues and supplies of moisture slowly dwindle, only the
  most drought-resistant of flowering plants continue to grow and to
  bloom. With the onset of autumn rains, only the tiny yellow blossoms
  of the sagebrush and rabbitbrush remain.

    [Illustration: _Blazing star_]

    [Illustration: _Monkeyflower_]

    [Illustration: _Desert parsley_]

    [Illustration: _Wild onion_]

    [Illustration: _Bitterroot_]

    [Illustration: _Paintbrush_]

    [Illustration: _Scabland penstemon_]

    [Illustration: _Arrow-leaved balsamroot_]

    [Illustration: _Scorpionweed_]


                               Mule Deer

    [Illustration: {uncaptioned}]

  Brad Griffith could be called the mule deer man. In 1980, this
  wildlife researcher began a three-year study of the mule deer herd
  that summers in the park. The immediate concern was that the deer,
  protected inside the park, might be overpopulating their range and
  endangering their habitat. Griffith set out to find out just how the
  deer use the area, what their population level is, and how certain
  factors—production, mortality, and distribution—affect their
  population dynamics. The mule deer use the park April through November
  only, because winter brings snows too deep for the deer to find food
  here. The most striking finding of Griffith’s research is that the
  mule deer at Craters of the Moon—unlike mule deer studied
  elsewhere—have a dual summer range. Put simply, the mule deer have had
  to undergo behavior modification to live here. The deer move back into
  the southern park in mid-April, living in the protected wilderness
  area there. While in the wilderness area, the park’s deer routinely
  live up to nearly 10 miles from open water, getting their water from
  food, dew, fog, and temporary puddles. This area has higher quality
  forage for these deer than any other part of their annual range. The
  trade-off is that the wilderness area has almost no open water. When
  the moisture content of their forage decreases in summer, usually in
  July, the deer move up to the northern part of the park where there is
  open water. Their habits in the northern part of the park are unusual,
  too, Griffith says, because there the deer live in much closer
  quarters than other herds are known to tolerate on summer ranges. They
  live in this wildlife equivalent of an apartment complex until the
  fall rains come. Then they move back down to the wilderness area. The
  deer make this unusual summer migration, Griffith suggests, to avail
  themselves of the high quality forage in the southern park. “The park
  serves as an island of high quality habitat for mule deer,” he wrote
  in his report. It is now known the deer will leave the wilderness area
  for the northern park after 12 days with daytime highs above 80°F and
  nighttime lows above 50°F in summer. “We can’t really predict this,”
  Park Ranger Neil King says, “but the deer know when this is.” What is
  happening is that the percentage of water in their forage plants falls
  below what is necessary to sustain the deer with increasingly hot
  weather. As you would expect, does nursing two fawns leave a couple
  days earlier than does with only one fawn. The rate at which their
  fawns survive to the fall of the year is astonishing. “This is an
  incredibly productive herd,” Griffith says, “right up there with the
  highest fawn survival rate of any western mule deer herd.” Park
  rangers continue Griffith’s studies by taking deer census counts.

    [Illustration: {Map showing fall, summer, and spring migrations}]

    [Illustration: _The Northern Shoshone regularly passed through the
    Craters of the Moon area on their annual summer migration from the
    Snake River to the Camas Prairie, west of the park. They took this
    journey to get out of the hot desert and into the cooler mountains.
    There they could gather root crops and hunt marmots, jackrabbits,
    porcupines, and ground squirrels. As they passed through today’s
    park, they left behind arrowheads, choppers, and scrapers and built
    stone circles that may have been used for ceremonial purposes. These
    artifacts and structures are evidence the Indians were temporary
    visitors to this vast volcanic landscape._]




           Indians, Early Explorers And Practicing Astronauts


Not surprisingly, archeologists have concluded that Indians did not make
their homes on this immense lava field. Astronauts would one day trek
about Craters of the Moon in hopes that experiencing its harshly alien
environment would make walking on the moon less disorienting for them.
No wonder people have not chosen to live on these hot, black, sometimes
sharp lava flows on which you must line the flight of doves to locate
drinking water.

Indians did traverse this area on annual summer migrations, however, as
shown by the developed trails and many sites where artifacts of Northern
Shoshone culture have been found. Most of these archeological sites are
not easily discerned by the untrained eye, but the stone windbreaks at
Indian Tunnel are easily examined. Rings of rocks that may have been
used for temporary shelter, hunting blinds, or religious purposes,
numerous stone tools, and the hammerstones and chippings of arrowhead
making are found scattered throughout the lava flows. Some of the
harder, dense volcanic materials found here were made into crude cutting
and scraping tools and projectile points. Such evidence suggests only
short forays into the lavas for hunting or collecting by small groups.

The Northern Shoshone were a hunting and gathering culture directly
dependent on what the land offered. They turned what they could of this
volcanic environment to their benefit. Before settlement by Europeans,
the vicinity of the park boasted several game species that are rare or
absent from Craters of the Moon today. These included elk, wolf, bison,
grizzly and black bear, and the cougar. Bighorn sheep, whose males sport
characteristic headgear of large, curled horns, have been absent from
the park since about 1920.

Military explorer U.S. Army Capt. B.L.E. Bonneville left impressions of
the Craters of the Moon lava field in his travel diaries in the early
1800s. In _The Adventures of Captain Bonneville_, which were based on
the diaries, 19th-century author Washington Irving pictures a place
“where nothing meets the eye but a desolate and awful waste, where no
grass grows nor water runs, and where nothing is to be seen but lava.”
Irving is perhaps most famous for _The Legend of Sleepy Hollow_, but his
_Adventures_ is considered a significant period work about the West and
provided this early, if brief, glimpse of a then unnamed Craters of the
Moon.

Pioneers working westward in the 19th century sought either gold or
affordable farm or ranch lands so they, like the Northern Shoshone,
bypassed these lava wastes. Later, nearby settlers would venture into
this area in search of additional grazing lands. Finding none, they left
Craters of the Moon substantially alone.

Early pioneers who left traces in the vicinity of the park did so by
following what eventually came to be known as Goodale’s Cutoff. The
route was based on Indian trails that skirted the lava fields in the
northern section of the park. It came into use in the early 1850s as an
alternate to the regular route of the Oregon Trail. Shoshone Indian
hostilities along the Snake River part of the trail—one such incident is
memorialized in Idaho’s Massacre Rocks State Park—led the emigrants to
search for a safer route. They were headed for Oregon, particularly the
Walla Walla area around Whitman Mission, family groups in search of
agricultural lands for settlement. Emigrants traveling it in 1854
noticed names carved in rocks and trees along its route. It was named in
1862 by travelers apparently grateful to their guide, Tim Goodale, whose
presence, they felt, had prevented Indian attacks. Illinois-born Goodale
was cut in the mold of the typical early trapper and trader of the Far
West. He was known to the famous fur trade brothers Solomon and William
Sublette. His name turned up at such fur trade locales as Pueblo, Taos,
Fort Bridger, and Fort Laramie over a period of at least 20 years.

After the discovery of gold in Idaho’s Salmon River country, a party of
emigrants persuaded Goodale to guide them over the route they would name
for him. Goodale was an experienced guide: in 1861, he had served in
that capacity for a military survey west of Denver. The large band of
emigrants set out in July and was joined by more wagons at Craters of
the Moon. Eventually their numbers included 795 men and 300 women and
children. Indian attacks occurred frequently along the Oregon Trail at
that time, but the size of this group evidently discouraged such
incursions. The trip was not without incident, but Goodale’s reputation
remained sufficiently intact for his clients to affix his name to the
route. Subsequent modifications and the addition of a ferry crossing on
the Snake River made Goodale’s Cutoff into a popular route for western
emigration. Traces of it are still visible in the vicinity of the park
today.

Curiosity about this uninhabitable area eventually led to more detailed
knowledge of Craters of the Moon and knowledge led to its preservation.
Geologists Israel C. Russell and Harold T. Stearns of the U.S.
Geological Survey explored here in 1901 and 1923, respectively.
Taxidermist-turned-lecturer Robert Limbert explored the area in the
early 1920s. Limbert made three trips. On the first two, he more or less
retraced the steps of these geologists. On his third and most ambitious
trek, Limbert and W. L. Cole traversed what is now the park and the
Craters of the Moon Wilderness Area south to north, starting from the
nearby community of Minidoka. Their route took them by Two Point Butte,
Echo Crater, Big Craters, North Crater Flow and out to the Old
Arco-Carey Road, then known as the Yellowstone Park and Lincoln Highway.
These explorations and their attendant publicity in _National Geographic
Magazine_ were instrumental in the proclamation of Craters of the Moon
as a national monument by President Calvin Coolidge in 1924.

Since Limbert’s day, astronauts have walked both here and on the moon.
Despite our now detailed knowledge of the differences between these two
places, the name—and much of the park’s awe-inspiring appeal—remains the
same. It is as though by learning more about both these niches in our
universe we somehow have learned more about ourselves as well.

    [Illustration: _In the mid-1800s the Oregon Trail served as a major
    route to the West for pioneers. But when hostilities developed along
    the trail with the Shoshone-Bannock Indians, many of the emigrants
    began using an alternate route known as Goodale’s Cutoff. This trail
    went further north and passed through the present-day park
    boundary._]

(_continued on page 52_)


               Early Explorers and the Limbert Expedition

    [Illustration: {uncaptioned}]

  The first known explorations of these lava fields were conducted by
  two Arco, Idaho, cattlemen in 1879. Arthur Ferris and J.W. Powell were
  looking for water for their livestock. The first scientific
  explorations were carried out by Israel C. Russell, surveying the area
  for the U.S. Geological Survey in 1901 and 1903. Beginning in 1910,
  Samuel A. Paisely, later to become the park’s first custodian, also
  explored these lava fields. In 1921, the U.S.G.S. sent two geologists
  here, Harold T. Stearns and O.E. Meinzer, with a geologist from the
  Carnegie Institute. Based on this field work, Stearns recommended that
  a national monument be created here. Also during the early 20s, the
  explorations of Idaho entrepreneur Robert W. Limbert caught the
  public’s fancy. A report of the explorations of “Two-gun” Bob Limbert
  was published in the March 1924 _National Geographic Magazine_.
  Limbert was a Boise, Idaho, taxidermist, tanner, and furrier. He was
  also an amateur wrestler and quick-draw artist who later performed on
  the national lecture circuit. Reportedly, Limbert once challenged Al
  Capone to a pistol duel at 10 paces. Evidently Capone declined.
  Limbert made three treks into the lava fields between 1921 and 1924.
  He first explored the more easily accessible northern portion of the
  lava fields. Limbert’s third expedition crossed the area from south to
  north, however, starting from Minidoka.


                                The Limbert Trek

    [Illustration: _On his third expedition, Limbert, Cole, and a dog
    traversed the lava flows from south to north. The photos that
    appeared in_ The National Geographic Magazine _in 1924 were taken on
    various expeditions._]

  With Limbert were W.L. Cole and an Airedale terrier. Taking the dog
  along was a mistake, Limbert wrote, “for after three days’ travel his
  feet were worn raw and bleeding.” Limbert said it was pitiful to watch
  the dog as it hobbled after them. The landscape was so unusual that
  Limbert and Cole had difficulty estimating distances. Things would be
  half again as far away as they had reckoned. In some areas their
  compass needles went wild with magnetic distortions caused by high
  concentrations of iron in the lava rock. Bizarre features they
  found—such as multi-colored, blow-out craters—moved Limbert to write:
  “I noticed that at places like these we had almost nothing to say.”
  Limbert and Cole discovered ice caves with ice stalactites. They found
  water by tracking the flights of mourning doves. They found pockets of
  cold water (trapped above ground by ice deposits below the surface)
  covered with yellowjackets fatally numbed by the cold. They drank the
  water anyway. In desert country, said Limbert, one can’t be too picky.
  Between Limbert’s lively article in the _National Geographic
  Magazine_, and the reports of geologist Stearns, President Calvin
  Coolidge was induced to designate part of the lava fields as Craters
  of the Moon National Monument on May 2, 1924.

    [Illustration: {untitled}]

    [Illustration: {untitled}]




                                 Part 3
                           Guide and Adviser


    [Illustration: ]




                    Approaching Craters of the Moon


_Craters of the Moon National Monument is located in south-central
Idaho’s Snake River Plain, midway between Boise, Idaho, and Grand Teton
and Yellowstone National Parks. The park includes 53,545 acres, and the
elevation at the visitor center is 5,900 feet above sea level. U.S.
20-26-93 gives access to the park. Nominal entrance fees are charged.
Golden Eagle, Golden Age, and Golden Access passports are honored and
may be obtained at the entrance station._


                          Seasons and Weather.

Park facilities are open and naturalist programs are conducted from
mid-June through Labor Day. From November to April, the Loop Drive (see
map) is closed by snow and park facilities are limited. In spring and
fall, the opening and closing of facilities and the Loop Drive are
determined by weather conditions, which vary greatly from year to year.
In spring the weather is unpredictable. Strong winds may occur and snow
and/or freezing rain are not uncommon. Temperatures range from highs in
the 50s to lows in the 20s°F. Summer features warm to hot days and cool
nights. Expect afternoon winds. There may be very sporadic afternoon
thunderstorms, and temperatures may range from the 40s to the 90s. Fall
offers generally fair weather with low precipitation and infrequent
winds. Early snowstorms are possible, and snow is certain by late fall.
Fall temperatures range from highs in the 60s to lows in the 30s. Winter
brings the possibility of severe storms with drifting snow. Highway
access is often best described as snow-packed. On bright sunny days
temperatures may reach into the 40s, but the range is generally from
highs in the 30s to lows around minus 10.

    [Illustration: _Today’s park encompasses a small portion of the
    Great Rift and the greater portion of the Craters of the Moon Lava
    Field near Arco, Idaho. Blue arrows on this map show the route of
    the Limbert Expeditions in the 1920s. The detail map appears on page
    58._]


  Limbert’s route
    From Minidoka.
    Two Point Butte
    Vermillion Chasm
    Sheep Trail Butte
    Echo Crater
      Bridge of Tears
    Big Cinder Butte
    Big Craters
    North Crater Flow
    Old Arco Carey Road
    Martin P.O.
  See detail map
    Visitor Center


                          Handicapped Access.

The park visitor center, restrooms, and amphitheater are accessible to
the disabled.


                            Travel Planning.

U.S. 20-26-93 provides access to Craters of the Moon. No public
transportation serves the park. Scheduled airlines serve Idaho Falls,
Twin Falls, and Hailey, Idaho. Rental cars are generally available at
these airports, but advance reservations are advised. It is about a
three-hour drive from the park to Grand Teton National Park, and about a
four-hour drive to Yellowstone National Park. The official Idaho State
Highway Map is available from the Idaho Transportation Department, P.O.
Box 7129, Boise, ID 83707, telephone (208) 334-8000. Idaho’s travel
office provides information about cultural activities, scenic tours,
outfitters and guides, chambers of commerce, hotels, and motels
throughout the state. Write or call Idaho’s Travel Promotion Division,
700 West State Street, Boise, ID 83720-2700, telephone (208) 334-2470.


                             Stay on Roads.

Please stay on roadways and parking pullouts that are provided. If a
vehicle goes off the roadway onto cinders, the cinders are compacted and
the tracks may remain visible for 10 to 20 years or more.

Information about the Park. Address specific inquiries about the park to
the Superintendent, Craters of the Moon National Monument, P.O. Box 29,
Arco, ID 83213, or telephone (208) 527-3257.

    [Illustration: _Make the visitor center your first stop in the park.
    Ask at the information desk for schedules of ranger-led walks,
    talks, and other programs and for advice about camping._]

    [Illustration: {uncaptioned}]




                      Visitor Center and Programs


The park visitor center is located near the only entrance to the park.
Here you will find displays and information to help you plan your visit.
Slides, postcards, maps, and other publications about the park are
displayed for sale. Park Service rangers at the information counter can
answer your questions and help you plan your stay in the park.

The displays alert you to wildflowers and wild animals you might expect
to see here. Other exhibits describe the park’s geologic history. A film
explains how lava flowed from fissures in the Earth to create the cinder
cones, lava flows, and other volcanic features you will see at Craters
of the Moon. The film includes actual footage of eruptions of the same
type that occurred here some 2,000 years ago. Check at the visitor
center for the schedules of conducted walks and campfire programs. You
also can get information here about two self-guiding nature trails and
the park’s Loop Drive (see page 59).


                    Activities and Evening Programs.

In summer, ranger-guided walks and other programs give visitors an
intimate look at various aspects of the park. Program schedules vary; we
suggest that you contact the park for current information prior to
arrival. Several sites have been designed to make it easy to see the
park on your own. The visitor center is a good place to stop and plan
your visit. Evening programs may find you wanting a sweater or light
jacket to ward off the chill, despite the hot summer days. These
programs explore such topics as the park’s wildlife and its survival,
the powers of nature, and this landscape’s volcanic origins. Some
programs are illustrated with slides or movies and take place in the
amphitheater.


                          Self-guiding Trails.

Explore three representative areas of the park on self-guiding nature
trails. Devils Orchard Trail helps you understand the complex
environmental concerns facing Craters of the Moon. A pamphlet available
at the trailhead discusses the major impacts visitors, neighbors, and
managers have on the fragile lava landscape. Numbered explanations
correspond to markers along the trail. You can walk this trail in about
20 minutes. North Crater Flow Trail takes you through a lava flow that
includes rafted blocks (crater wall fragments) and other interesting
features characteristic of basaltic lava flows, which are explained by
wayside exhibits. This trail goes through one of the most recent lava
flows in the park. The shiny lava flows made early explorers think the
volcanic eruptions had happened only a few years before. Please stay on
trails in this very fragile area. The park was established to provide
protection for its unusual landscape features. These require continuing
protection and you can help provide it. Caves Trail allows you the
opportunity to explore a lava tube. These caves formed when the surface
of lava flow cooled and hardened while the interior remained molten and
continued to drain. After the lava drained away, a hollow tube remained.
A pamphlet at the trailhead provides a map of the cave area and tells
you what to expect as you explore these lava tubes on your own. Wayside
exhibits point out the most interesting lava formations along the trail.
To see only Indian Tunnel, the largest of the lava tubes, will require
nearly one hour.

    [Illustration: _Visitors read a wayside exhibit beneath imposing
    monoliths. Flows of lava rafted such fragments of broken crater
    walls into otherwise inexplicable positions._]




                                  Map


[Illustration: Craters of the Moon National Monument]


  Wilderness area
    Grassy Cone
      1925 m
      _6315 ft_
    Sunset Cone
      1954 m
      _6415 ft_
  Backcountry area
  Trail
  Point of interest
  ①
    Visitor Center
      To Arco
      To Carey
    Campground
  ②
    North Crater Flow Trail
    North Crater Trail
      Silent Cone
        1838 m
        _6357 ft._
      North Crater
        1908 m
        _8244 ft_
  ③
    Devils Orchard Nature Trail
    Paisley Cone
      1881 m
      _6107 ft_
  ④
    Inferno Cone
      1884 m
      _6181 ft_
  ⑤
    Snow Cone
    Spatter Cones
    North Crater Trail
  ⑥
    GREAT RIFT ZONE
    BIG SINK
    Broken Top
      1846 m
      _5058 ft_
    Buffalo Cave
    Half Cone
      1845 m
      _5055 ft_
    Big Cinder Butte
      1988 m
      _5516 ft_
    TREE MOLDS
  ⑦
    Dewdrop Cave
    Surprise Cave
    Beauty Cave
    Boy Scout Cave
    Indian Tunnel
  PIONEER MOUNTAINS
  GREEN DRAGON FLOWS
  SERRATE FLOW
  BLUE DRAGON FLOWS
  BROKEN TOP FLOW
  LAVA CASCADES
  BIG CRATERS




                         Take The Driving Tour


You can see most of the features for which Craters of the Moon is famous
by a combined auto and foot tour along the Loop Drive. With several
short walks included, you can make the drive in about two hours.
Numbered stops are keyed to the map in the park folder.

1. Visitor Center. The 7-mile Loop Drive begins at the visitor center.
Most of the drive is one-way. Spur roads and trailheads enable you to
explore this lava field even further.

2. North Crater Flow. A short foot trail crosses the North Crater Flow
to a group of crater wall fragments transported by lava flows. This is
one of the youngest flows here. The triple twist tree and its 1,350
growth rings have in the past helped date the recency of the last flows
here. Along this trail you can see fine examples of pahoehoe lava and aa
lava flows (see page 26). Just beyond the North Crater Flow Trail is the
North Crater Trail. This short, steep, self-guiding nature trail leads
you to the vent overlooking the crater of a cinder cone.

3. Devils Orchard. Devils Orchard is a group of lava fragments that
stand like islands in a sea of cinders. This marks the resting place for
blocks of material from the walls of North Crater that broke free and
were rafted here on lava flows. The short spur road leads to a
self-guiding trail through these weird features. You can easily walk the
trail in about 20 minutes. An early morning or evening visit may allow
you to observe park wildlife. In springtime, the wildflower displays in
the cinder gardens are glorious. In June and early July, dwarf blooming
monkeyflowers give the ground a magenta cast.

4. Inferno Cone Viewpoint. From the viewpoint atop Inferno Cone, a
landscape of volcanic cinder cones spreads before you to the distant
mountain ranges beyond. Notice that the cooler, moister northern slopes
of the cones bear noticeably more vegetation than the drier southern
slopes, which receive the brunt of sunshine. If you take the short,
steep walk to the summit of Inferno Cone, you can easily recognize the
chain of cinder cones that defines the Great Rift. Perhaps nowhere else
in the park is it so easy to visualize how the volcanic activity broke
out along this great fissure in the Earth. Towering in the distance
above the lava plain is Big Cinder Butte, one of the world’s largest,
purely basaltic, cinder cones.

5. Big Craters and Spatter Cones Area. Spatter cones formed along the
Great Rift fissure where clots of pasty lava stuck together when they
fell. The materials and forces of these eruptions originated at depths
of approximately 40 miles within the Earth. A short, steep walk to the
top of Big Craters offers a view of a series of volcanic vents.

6. Trails to Tree Molds and the Wilderness Area. A spur road just beyond
Inferno Cone takes you to trails to the Tree Molds Area and the Craters
of the Moon Wilderness. Tree molds formed where molten lava flows
encased trees and then hardened (see page 27). The cylindrical molds
that remained after the wood burned and rotted away range from a few
inches to more than 1 foot in diameter.

7. Cave Area. At this final stop on the Loop Drive, a ½-mile walk takes
you to the lava tubes. Here you can see Dewdrop, Boy Scout, Beauty, and
Surprise Caves and the Indian Tunnel. (For how these lava tubes formed,
see page 30.) Carry a flashlight in all caves except Indian Tunnel.




                      Camping and Backcountry Use


The campground has about 50 sites. These are available on a first-come,
first-served basis. Reservations are not accepted. A daily fee for
camping is charged. Water and restrooms are provided in the campground,
but there are no showers, dump station, or hookups. Wood fires are
prohibited in the park, but grills at each campsite may be used for
charcoal fires. The campground accommodates both RVs and tents. During
the summer, park rangers present evening programs at the campground
amphitheater.


                            Backcountry Use.

Some of the park’s most intriguing landscapes lie beyond the road’s end
in the 68-square-mile Craters of the Moon Wilderness Area. Only two
trails penetrate the wilderness, and these for only short distances.
After the three-mile trail to Echo Crater runs out, you are on your own.
For further exploration, you can simply follow the Great Rift and its
chain of cinder cones. These landmarks help you find your way.

To explore farther afield, you should have a good topographic map and
basic map skills. You can purchase such a map at the visitor center. All
hikers who plan to stay overnight in the wilderness are required to
register with a park ranger. Backcountry use permits are available free
at the visitor center.

Each hiker should carry at least one gallon of water for each day out;
even more may be necessary during the hot summer. There is no drinking
water available in the wilderness. The best times for wilderness travel
are May-June and September-October. Daytime temperatures are usually
mild then, while nights are cool, but you must be prepared for inclement
and very cold weather in these transitional months. Summer daytime
temperatures climb into the 90s, and reflected heat off the lavas may be
even higher. Long distance hiking is not very pleasant then, and the
weight of necessary drinking water is burdensome.


                                Safety.

Sturdy boots and long pants are necessary gear for the jagged aa lava
flows. Bring clothing for both hot and cool weather; both can occur the
same day in this desert climate. (See drinking water warning above.)


                              Regulations.

Campfires are prohibited in the backcountry. Carry a self-contained
backpack stove and fuel. Mechanized vehicles, including bicycles, are
prohibited in the wilderness area. Pets are also prohibited in the
wilderness. Pack out everything that you pack in—and any trash you find
that others left behind. A good admonition is: “Take only pictures, and
try not to leave so much as a footprint.”




                           Winter Recreation


The visitor center is open every day except winter holidays. Winter
hours are 8 a.m. to 4:30 p.m. Wilderness permits, topographic maps, and
information are available here. To find out about current snow
conditions, call (208) 527-3257.

Skiing. Crosscountry skiing provides an enjoyable experience of the
park’s landscape transformed by snow. When heavy snows accumulate,
usually in late November, the 7-mile Loop Drive is closed and it becomes
a natural ski trail. Most of the Loop Drive follows fairly level
terrain. The best months for skiing are January to March in most
winters. Usually there is about 18 inches of snowpack by January and 3
feet by March. Temperatures range from 45°F to well below zero. Be
prepared for inclement weather and high winds at all times. Blizzards
may be encountered.

Hazards. Skiing off the Loop Drive is allowed but not recommended. Most
of the park is covered by sharp, jagged lava, and snow cover may mask
cracks and caverns underneath.

Camping. Winter camping is permitted in the main campground. The
campground is not plowed; be prepared to camp in the snow. Wood fires
are not permitted anywhere in the park.

Wilderness use. The wilderness is ideal for overnight ski trips. You
should be well equipped and experienced at winter camping, however. A
free wilderness use permit, available at the visitor center, is required
for all overnight use outside the park campground.

    _Both backpackers and crosscountry skiers find solitude in their
    respective seasons in the park. Others may prefer ranger-led
    explorations of the park’s many unusual features._

    [Illustration: Backpackers]

    [Illustration: Crosscountry skiers]

    [Illustration: Ranger-led explorations]




                         Regulations and Safety


Many management concerns, regulations, and safety tips are given under
specific subjects in this handbook. Here are some other things to
consider.

Precautions must be taken when you explore the park because of the
rugged terrain, heat, and lack of naturally available drinking water.
You will need sturdy boots, a hat, and ample, leakproof water
containers. Make sure containers are watertight before you leave home.
Exploring caves requires flashlights.

Camp only in the park campground. All other overnight use, even in
winter, requires a wilderness use permit. A day-use permit is required
to visit the area of the park that lies north of Highway 20-26-93.


                                 Pets.

Pets are allowed only in the campground and on the Loop Drive, but they
must be kept on a leash at all times. Pets are prohibited in all public
buildings, on trails, or in off-road areas.


                               Vehicles.

All motor vehicles and bicycles must stay on paved roads only. They are
not allowed on trails.


                               Firearms.

Firearm restrictions are enforced: No hunting is allowed in the park.


                              Collecting.

The collection, removal, or disturbance of any natural features within
the park is strictly prohibited.

    [Illustration: _For contemporary explorers the driving tour and its
    associated trails make the safest trek routes. Exercise great
    caution—and close oversight of young children—at all times on your
    park expeditions._]

    [Illustration: {trail}]




                           Nearby Attractions


Yellowstone National Park is world famous for its geysers and mudpots,
canyons and waterfalls, and wildlife and wilderness. For information
write or call, Superintendent, Yellowstone National Park, WY 82190,
(307) 344-7381.

    [Illustration: _Minerva Terrace, Yellowstone_]


Grand Teton National Park features the spectacularly scenic Teton Range
and lovely lakes at its base. John D. Rockefeller, Jr., Memorial Parkway
joins Grand Teton with Yellowstone. For information write or call,
Superintendent, Grand Teton National Park, P.O. Drawer 170, Moose, WY
83012, (307) 733-2880.

    [Illustration: _Grand Teton in winter_]


Nez Perce National Historical Park includes 24 widely scattered sites in
north-central Idaho that present the history of this ancestral homeland
of the Nez Perce tribe. For information write or call, Superintendent,
Nez Perce National Historical Park, P.O. Box 93, Spalding, ID 83551,
(208) 843-2261.

    [Illustration: _A Nez Perce today_]


Hagerman Fossil Beds National Monument, authorized in 1988, preserves
Pliocene fossil sites along Idaho’s Snake River. The National Park
Service is planning for future needs. Facilities have not been
developed. For information write or call, Superintendent, Hagerman
Fossil Beds National Monument, P.O. Box 570, Hagerman, ID 83332, (208)
837-4793.


City of Rocks National Reserve is a fascinating landscape of monoliths,
spires, and domes used historically by Northern Shoshone Indians and
emigrants on the California Trail. It has become a mecca for
recreational rock climbers. Primitive facilities. For information write,
Manager, City of Rocks National Reserve, P.O. Box 169, Almo, ID 83312.




                         Armchair Explorations


The nonprofit Craters of the Moon Natural History Association sells
books, maps, and other publications at the visitor center or by mail.
For a free list write to the park address on page 55. The following
selected books may also be of interest.

Belknap, William J. “Man on the Moon in Idaho,” _National Geographic
Magazine_, Volume 119 (October, 1960).

Bonnichsen, Bill and Roy M. Breckenridge et al. _Cenozoic Geology of
Idaho_, Idaho Geologic Survey, University of Idaho, 1982.

Bullard, Fred M. _Volcanoes of the Earth_, University of Texas Press,
1976.

Chronic, Halka. _Pages of Stone: The Geologic Story of Our Western Parks
and Monuments_, The Mountaineers, 1984.

Clark, David R. _Craters of the Moon—Idaho’s Unearthly Landscape_,
Craters of the Moon Natural History Association, 1990.

Henderson, Paul A. _Around the Loop: Craters of the Moon_, Craters of
the Moon Natural History Association, 1986.

Limbert, Robert W. “Among Craters of the Moon,” _National Geographic
Magazine_, Volume 45 (March, 1924).

McKee, Bates. _Cascadia_, McGraw-Hill, 1972.

Moser, Don. _The Snake River Country_, Time-Life Books, 1974.

National Aeronautics and Space Administration (NASA). _Volcanism of the
Eastern Snake River Plain, Idaho: A Comparative Planetary Geology
Guidebook_, Washington, D.C., 1977.

Schwartz, Susan. _Nature in the Northwest_, Prentice-Hall, 1983.


Other National Park Handbooks in this series. You might enjoy other
official National Park Handbooks about areas in Idaho, Wyoming, and
Montana. These handbooks include: Grand Teton National Park; Nez Perce
National Historical Park; Devils Tower National Monument; and Fort
Laramie National Historic Site.

These informative handbooks are available at the parks or by mail from:
Superintendent of Documents, U.S. Government Printing Office,
Washington, DC 20402. For a list of handbooks write to: National Park
Service, Office of Information, P.O. Box 37127, Washington, DC
20013-7127.


★GPO: 1990—262-098/20002




                         National Park Service
                    U.S. Department of the Interior


As the Nation’s principal conservation agency, the Department of the
Interior has responsibility for most of our nationally owned public
lands and natural resources. This includes fostering wise use of our
land and water resources, protecting our fish and wildlife, preserving
the environmental and cultural values of our national parks and
historical places, and providing for the enjoyment of life through
outdoor recreation. The Department assesses our energy and mineral
resources and works to assure that their development is in the best
interest of all our people. The Department also promotes the goals of
the Take Pride in America campaign by encouraging stewardship and
citizen responsibility for the public lands and promoting citizen
participation in their care. The Department also has major
responsibility for American Indian reservation communities and for
people who live in island territories under U.S. administration.

The National Park Service expresses its appreciation to all those
persons who made the preparation and production of this handbook
possible. Special thanks are due the Craters of the Moon Natural History
Association for financial support. Unless credited below, photographs
and illustrations come from the files of Craters of the Moon National
Monument and the National Park Service.


  Gary Braasch 28 top
  Bureau of Land Management 29 top
  Vern Crawford 30-31
  Jeff Gnass 4-5, 6, 27 tree mold
  Charley Gurche 10-11, 32-33, 36 monkeyflower
  Russell Lamb 63 Nez Perce
  Roger McGehee 30 owl
  NASA 16 inset
  National Geographic Society 50-51, 63 Grand Teton (David Alan Harvey)
  U.S. Geological Survey 25 both
  Glenn Van Nimwegen 34, 36-37
  Williams and Heintz Map Corporation 58




                          Transcriber’s Notes


—Retained publication information from the printed edition: this eBook
  is public-domain in the country of publication.

—Relocated all image captions to be immediately under the corresponding
  images, removing redundant references like ”preceding page”.

—Silently corrected a few palpable typos.

—In the text versions only, text in italics is delimited by
  _underscores_.