1. Native Americans in traditional dress.
The human history of the Yellowstone region goes back more than 11,000 years. From about 11,000
years ago to the very recent past, many groups of Native Americans used the park as their homes,
hunting grounds, and transportation routes. These traditional uses of Yellowstone lands continued until
a little over 200 years ago when the first people of European descent found their way into the park. In
1872 a country that had not yet seen its first centennial established Yellowstone as the first national
park in the world. A new concept was born and with it a new way for people to preserve and protect the
best of what they had for the benefit and enjoyment of future generations.
http://www.nps.gov/yell/historyculture/index.htm
Did You Know?
Yellowstone contains approximately one-half of the world’s hydrothermal
features. There are over 10,000 hydrothermal features, including over 300
geysers, in the park.
http://www.nps.gov/yell/historyculture/people.htm
Did You Know?
The 1988 fires affected 793,880 acres or 36 percent of the park. Five fires
burned into the park that year from adjacent public lands. The largest, the
North Fork Fire, started from a discarded cigarette. It burned more than
410,000 acres.
http://www.nps.gov/yell/historyculture/preservation.htm
http://www.backcountry-adventures.com/m

2. Fishing in Yellowstone
Yellowstone National Park is managed to protect cultural and natural resources and outstanding
scenery, and to provide for visitor use. Fishing has been a major visitor activity for well over a century.
Because of this history, fishing continues to be allowed and can complement, and in some cases even
enhance, the park’s primary purpose to preserve natural environments and native species.

3. NPS/KOEL
Yellowstone National Park Aquatic Ecologist searching for amphibians along a lake margin.
Native vs. Nonnative Fishes in Yellowstone
Yellowstone has 13 fish native to its lakes and streams. Native sport fish include three subspecies of
cutthroat trout, fluvial arctic grayling, and mountain whitefish. Non-native fish species that were
introduced to the park in the late 19th and early 20th centuries include rainbow trout, brown trout,
brook trout, and lake trout. Although non-native trout are also important to the angler experience in
Yellowstone, they have contributed to a decline in the park’s native cutthroat trout and fluvial arctic
grayling, especially recently.
History of Fisheries Management
When Yellowstone became a national park, almost 40 percent of Yellowstone’s waters were
naturally barren of fish—including Shoshone Lake, Lewis Lake, and the Firehole River above Firehole
Falls. Early park managers thought it necessary to plant fish into new locations, produce more fish in
hatcheries, and introduce non-native species. By the mid-20th century, more than 310 million fish
had been stocked in Yellowstone. Because of the realization that many of these activities were
harmful to the park, stocking of fishes in the park ended in 1956.
PHOTO COURTESY OF HUNTER HUTCHINSON
River otter consuming a Yellowstone cutthroat trout in a high mountain lake.
Current Status of Native Species

4. Maintaining the Ecological Integrity of the Park
In Yellowstone, bald eagles, ospreys, pelicans, otters, grizzly bears, and other wildlife take precedence
over humans in utilizing fish as food. Fishing management and regulations reflect this priority and that
of maintaining fish populations that have sufficient number of spawning adults to maintain natural
reproduction and genetic diversity.
Because of the increasing number of anglers in the park, more restrictive regulations have been adopted
in Yellowstone. These restrictions include season opening and closing dates, restrictive use of bait,
catch-and-release only for native fish, and number/size limits for nonnative species. Some waters are
closed to fishing to protect threatened and endangered species, sensitive nesting birds, and to provide
scenic viewing areas for visitors seeking undisturbed wildlife
Did You Know?
You cannot fish from Fishing Bridge. Until 1973 this was a very popular fishing
location since the bridge crossed the Yellowstone River above a cutthroat
trout spawning area. It is now a popular place to observe fish.
Photo by Joe Facendola
Fishing in Yellowstone
Yellowstone National Park is managed to protect cultural and natural resources and outstanding
scenery, and to provide for visitor use. Fishing has been a major visitor activity for well over a century.
Because of this history, fishing continues to be allowed and can complement, and in some cases even
enhance, the park’s primary purpose to preserve natural environments and native species.

5. http://www.nps.gov/yell/planyourvisit/fishing.htm
Did You Know?
There were no wolves in Yellowstone in 1994. The wolves that were
reintroduced in 1995 and 1996 thrived and there are now over 300 of their
descendents living in the Greater Yellowstone Area.
http://www.nps.gov/yell/naturescience/fish_science.htm
The Mammoth area exhibits much evidence of glacial activity from the Pinedale Glaciation.
Mammoth Hot Springs
Mammoth Hot Springs are a surficial expression of the deep volcanic forces at work in Yellowstone.
Although these springs lie outside the caldera boundary, their energy is attributed to the same
magmatic system that fuels other Yellowstone thermal areas. Hot water flows from Norris to Mammoth
along a fault line roughly associated with the Norris to Mammoth road. Shallow circulation along this
corridor allows Norris' super-heated water to cool somewhat before surfacing at Mammoth, generally at
about 170° F.
http://www.nps.gov/yell/naturescience/geomammoth.htm

6. Norris Area Geologic Highlights
Norris sits on the intersection of three major faults. The Norris-Mammoth Corridor is a fault that
runs from Norris north through Mammoth to the Gardiner, Montana, area. The Hebgen Lake fault
runs from northwest of West Yellowstone, Montana, to Norris. This fault experienced an earthquake
in 1959 that measured 7.4 on the Richter scale (sources vary on exact magnitude between 7.1 and
7.8). These two faults intersect with a ring fracture that resulted from the Yellowstone Caldera of
600,000 years ago. These faults are the primary reason that Norris Geyser Basin is so hot and
dynamic. The Ragged Hills that lie between Back Basin and One Hundred Springs Plain are thermally
altered glacial moraines. As glaciers receded, the underlying thermal features began to express
themselves once again, melting remnants of the ice and causing masses of debris to be dumped.
These debris piles were then altered by steam and hot water flowing through them.
Madison lies within the eroded stream channels cut through lava flows formed after the caldera
eruption. The Gibbon Falls lies on the caldera boundary as does Virginia Cascades.
http://www.nps.gov/yell/naturescience/geonorris.htm
Canyon Area Geologic Highlights

7. The Grand Canyon of the Yellowstone
The specifics of the geology of the canyon are not well understood, except that it is an erosional
feature rather than the result of glaciation. After the caldera eruption of about 600,000 years ago,
the area was covered by a series of lava flows. The area was also faulted by the doming action of the
caldera before the eruption. The site of the present canyon, as well as any previous canyons, was
probably the result of this faulting, which allowed erosion to proceed at an accelerated rate. The
area was also covered by the glaciers that followed the volcanic activity. Glacial deposits probably
filled the canyon at one time, but have since been eroded away, leaving little or no evidence of their
presence.
The canyon below the Lower Falls was at one time the site of a geyser basin that was the result of
rhyolite lava flows, extensive faulting, and heat beneath the surface (related to the hot spot). No
one is sure exactly when the geyser basin was formed in the area, although it was probably present
at the time of the last glaciation. The chemical and heat action of the geyser basin caused the
rhyolite rock to become hydrothermally altered, making it very soft and brittle and more easily
erodible (sometimes likened to baking a potato). Evidence of this thermal activity still exists in the
canyon in the form of geysers and hot springs that are still active and visible. The Clear Lake area
(Clear Lake is fed by hot springs) south of the canyon is probably also a remnant of this activity.
According to Ken Pierce, U.S. Geological Survey geologist, at the end of the last glacial period, about
14,000 to 18,000 years ago, ice dams formed at the mouth of Yellowstone Lake. When the ice dams
melted, a great volume of water was released downstream causing massive flash floods and
immediate and catastrophic erosion of the present-day canyon. These flash floods probably
happened more than once. The canyon is a classic V-shaped valley, indicative of river-type erosion
rather than glaciation. The canyon is still being eroded by the Yellowstone River.
The colors in the canyon are also a result of hydrothermal alteration. The rhyolite in the canyon
contains a variety of different iron compounds. When the old geyser basin was active, the "cooking"
of the rock caused chemical alterations in these iron compounds. Exposure to the elements caused
the rocks to change colors. The rocks are, in effect, oxidizing; the canyon is rusting. The colors
indicate the presence or absence of water in the individual iron compounds. Most of the yellows in
the canyon are the result of iron present in the rock rather than sulfur, as many people think.
http://www.nps.gov/yell/naturescience/geocanyon.htm
Old Faithful Area Geologic Highlights

8. Evidence of the geological forces that have shaped Yellowstone are found in abundance in this
district. The hills surrounding Old Faithful and the Upper Geyser Basin are reminders of Quaternary
rhyolitic lava flows. These flows, occurring long after the catastrophic eruption of 600,000 years ago,
flowed across the landscape like stiff mounds of bread dough due to their high silica content.
Evidence of glacial activity is common, and it is one of the keys that allows geysers to exist. Glacier
till deposits underlie the geyser basins providing storage areas for the water used in eruptions. Many
landforms, such as Porcupine Hills north of Fountain Flats, are comprised of glacial gravel and are
reminders that as recently as 13,000 years ago, this area was buried under ice.
Signs of the forces of erosion can be seen everywhere, from runoff channels carved across the sinter
in the geyser basins to the drainage created by the Firehole River.
Mountain building is evident as you drive south of Old Faithful, toward Craig Pass. Here the Rocky
Mountains reach a height of 8,262 feet, dividing the country into two distinct watersheds.
Yellowstone is a vast land containing a landscape that is continually being shaped by geological
forces.
http://www.nps.gov/yell/naturescience/geooldfaith.htm
Yellowstone National Park
Hydrothermal Features and How They Work

9. Photo: NPS/Taylor
Heart Spring
With half of the earth’s geothermal features, Yellowstone holds the planet’s most diverse and intact
collection of geysers, hot springs, mudpots, and fumaroles. Its more than 300 geysers make up two
thirds of all those found on earth. Combine this with more than 10,000 thermal features comprised of
brilliantly colored hot springs, bubbling mudpots, and steaming fumaroles, and you have a place like
no other. Geyserland, fairyland, wonderland--through the years, all have been used to describe the
natural wonder and magic of this unique park that contains more geothermal features than any other
place on earth.
Yellowstone’s vast collection of thermal features provides a constant reminder of the park’s recent
volcanic past. Indeed, the caldera provides the setting that allows such features as Old Faithful to exist
and to exist in such great concentrations.
http://www.nps.gov/yell/naturescience/geothermal.htm
Hot Springs and How They Work

10. Emerald Spring
Norris Geyser Basin
In the high mountains surrounding the Yellowstone Plateau, water falls as snow or rain and slowly
percolates through layers of porous rock, finding its way through cracks and fissures in the earth’s
crust created by the ring fracturing and collapse of the caldera. [View the anatomy of a hot spring.]
Sinking to a depth of nearly 10,000 feet, this cold water comes into contact with the hot rocks
associated with the shallow magma chamber beneath the surface. As the water is heated, its
temperatures rise well above the boiling point to become superheated. This superheated water,
however, remains in a liquid state due to the great pressure and weight pushing down on it from
overlying rock and water. The result is something akin to a giant pressure cooker, with water
temperatures in excess of 400°F.
The highly energized water is less dense than the colder, heavier water sinking around it. This
creates convection currents that allow the lighter, more buoyant, superheated water to begin its
slow, arduous journey back toward the surface through rhyolitic lava flows, following the cracks,
fissures, and weak areas of the earth’s crust. Rhyolite is essential to geysers because it contains an
abundance of silica, the mineral from which glass is made. As the hot water travels through this
"natural plumbing system," the high temperatures dissolve some of the silica in the rhyolite, yielding
a solution of silica within the water.
At the surface, these silica-laden waters form a rock called geyserite, or sinter, creating the massive
geyser cones; the scalloped edges of hot springs; and the expansive, light- colored, barren landscape
characteristic of geyser basins. While in solution underground, some of this silica deposits as
geyserite on the walls of the plumbing system forming a pressure-tight seal, locking in the hot water
and creating a system that can withstand the great pressure needed to produce a geyser.
With the rise of superheated water through this complex plumbing system, the immense pressure
exerted over the water drops as it nears the surface. The heat energy, if released in a slow steady
manner, gives rise to a hot spring, the most abundant and colorful thermal feature in the park. Hot
springs with names like Morning Glory, Grand Prismatic, Abyss, Emerald, and Sapphire, glisten like
jewels in a host of colors across the park’s harsh volcanic plain.
Hot Springs and How They Work

11. Emerald Spring
Norris Geyser Basin
In the high mountains surrounding the Yellowstone Plateau, water falls as snow or rain and slowly
percolates through layers of porous rock, finding its way through cracks and fissures in the earth’s
crust created by the ring fracturing and collapse of the caldera. [View the anatomy of a hot spring.]
Sinking to a depth of nearly 10,000 feet, this cold water comes into contact with the hot rocks
associated with the shallow magma chamber beneath the surface. As the water is heated, its
temperatures rise well above the boiling point to become superheated. This superheated water,
however, remains in a liquid state due to the great pressure and weight pushing down on it from
overlying rock and water. The result is something akin to a giant pressure cooker, with water
temperatures in excess of 400°F.
The highly energized water is less dense than the colder, heavier water sinking around it. This
creates convection currents that allow the lighter, more buoyant, superheated water to begin its
slow, arduous journey back toward the surface through rhyolitic lava flows, following the cracks,
fissures, and weak areas of the earth’s crust. Rhyolite is essential to geysers because it contains an
abundance of silica, the mineral from which glass is made. As the hot water travels through this
"natural plumbing system," the high temperatures dissolve some of the silica in the rhyolite, yielding
a solution of silica within the water.
At the surface, these silica-laden waters form a rock called geyserite, or sinter, creating the massive
geyser cones; the scalloped edges of hot springs; and the expansive, light- colored, barren landscape
characteristic of geyser basins. While in solution underground, some of this silica deposits as
geyserite on the walls of the plumbing system forming a pressure-tight seal, locking in the hot water
and creating a system that can withstand the great pressure needed to produce a geyser.
With the rise of superheated water through this complex plumbing system, the immense pressure
exerted over the water drops as it nears the surface. The heat energy, if released in a slow steady
manner, gives rise to a hot spring, the most abundant and colorful thermal feature in the park. Hot
springs with names like Morning Glory, Grand Prismatic, Abyss, Emerald, and Sapphire, glisten like
jewels in a host of colors across the park’s harsh volcanic plain.
Did You Know?
The Roosevelt Arch is located at the North Entrance to Yellowstone National
Park. The cornerstone of the arch was laid by President Theodore Roosevelt.

12. Mudpots and How They Work
Bubbling Mudpot
Where hot water is limited and hydrogen sulfide gas is present (emitting the "rotten egg" smell
common to thermal areas), sulfuric acid is generated. The acid dissolves the surrounding rock into
fine particles of silica and clay that mix with what little water there is to form the seething and
bubbling mudpots. The sights, sounds, and smells of areas like Artist and Fountain paint pots and
Mud Volcano make these curious features some of the most memorable in the park
http://www.nps.gov/yell/naturescience/mudpots.htm
Fumaroles and How They Work
Black Growler Steam Vent
Norris Geyser Basin
Fumaroles, or steam vents, are hot springs with a lot of heat, but so little water that it all boils away
before reaching the surface. At places like Roaring Mountain, the result is a loud hissing vent of
steam and gases.

13. Did You Know?
The 1988 fires affected 793,880 acres or 36 percent of the park. Five fires
burned into the park that year from adjacent public lands. The largest, the
North Fork Fire, started from a discarded cigarette. It burned more than
410,000 acres
http://www.nps.gov/yell/naturescience/fumaroles.htm
Mammoth Terraces and How They Work
At Mammoth Hot Springs, a rarer kind of spring is born when the hot water ascends through the
ancient limestone deposits of the area instead of the silica-rich lava flows of the hot springs
common elsewhere in the park. The results are strikingly different and unique. They invoke a
landscape that resembles a cave turned inside out, with its delicate features exposed for all to see.
The flowing waters spill across the surface to sculpt magnificent travertine limestone terraces. As
one early visitor described them, "No human architect ever designed such intricate fountains as
these. The water trickles over the edges from one to another, blending them together with the
effect of a frozen waterfall."
How They Work
As ground water seeps slowly downward and laterally, it comes in contact with hot gases charged
with carbon dioxide rising from the magma chamber. Some carbon dioxide is readily dissolved in the
hot water to form a weak carbonic acid solution. This hot, acidic solution dissolves great quantities
of limestone as it works up through the rock layers to the surface hot springs. Once exposed to the
open air, some of the carbon dioxide escapes from solution. As this happens, limestone can no
longer remain in solution. A solid mineral reforms and is deposited as the travertine that forms the
terraces.

14. Did You Know?
Prior to the establishment of the National Park Service, the U.S. Army
protected Yellowstone between 1886 and 1918. Fort Yellowstone was
established at Mammoth Hot Springs for that purpose.
http://www.nps.gov/yell/naturescience/mamterr.htm
Geysers and How They Work

15. Sprinkled amid the hot springs are the rarest fountains of all, the geysers. What makes them rare
and distinguishes them from hot springs is that somewhere, usually near the surface in the plumbing
system of a geyser, there are one or more constrictions.
View animation of how geysers work.
View Geyser Ingredients (Flash animation)
Expanding steam bubbles generated from the rising hot water build up behind these constrictions,
ultimately squeezing through the narrow passageways and forcing the water above to overflow
from the geyser. The release of water at the surface prompts a sudden decline in pressure of the
hotter waters at great depth, triggering a violent chain reaction of tremendous steam explosions in
which the volume of rising, now boiling, water expands 1,500 times or more. This expanding body of
boiling superheated water bursts into the sky as one of Yellowstone’s many famous geysers.
There are more geysers here than anywhere else on earth. Old Faithful, certainly the most famous
geyser, is joined by numerous others big and small, named and unnamed. Though born of the same
water and rock, what is enchanting is how differently they play in the sky. Riverside Geyser shoots at
an angle across the Firehole River, often forming a rainbow in its mist. Castle erupts from a cone
shaped like the ruins of some medieval fortress. Grand explodes in a series of powerful bursts,
towering above the surrounding trees. Echinus spouts up and out to all sides like a fireworks display
of water. And Steamboat, the largest in the world, pulsates like a massive steam engine in a rare,
but remarkably memorable eruption, reaching heights of 300 to 400 feet.
Technical information about our geysers is available through the following non-NPS source.
Yellowstone Geysers - courtesy of David Montieth & Contributors
http://www.nps.gov/yell/naturescience/geysers.htm
Hot Spot Theories

16. Two Hotspot Theories
MOLTEN ROCK, or magma, rises in convection cells, like water boiling in a pot. The left side of this illustration shows the tra
hotspot as a plume of magma rising from the earth's core. The right side shows another theory that the Yellowstone hotsp
shallower depth.
View Caldera | Caldera Rim |Track the Hotspot | Eruptions
http://www.nps.gov/yell/naturescience/hotspottheory.htm
Nature & Wildlife
Nature & Wildlife //
Last:Nature & Wildlife
• Yellowstone Wolves
• Bison
• Bears & Bear Safety
• Elk
• Moose
• Antelope
• Bighorn Sheep
• Birds
• Bobcats
• Coyotes
• Mountain Goats
• Mountain Lions
• Mule Deer
http://www.yellowstoneparknet.com/nature_wildlife/
Definition of national park EUA
The quality of national significance is ascribed to collections and historic properties that possess
exceptional value or quality in illustrating or interpreting the intellectual and cultural heritage and the
built environment of the United States, that possess a high degree of integrity and that:
• Are associated with events that have made a significant contribution to, and are identified with, or
that outstandingly represent the broad patterns of United States history and culture and from which an

17. understanding and appreciation of those patterns may be gained; or,
• Are associated importantly with the lives of persons nationally significant in the United States history
or culture; or,
• Represent great historic, cultural, artistic or scholarly ideas or ideals of the American people; or,
• Embody the distinguishing characteristics of a resource type that:
• Is exceptionally valuable for the study of a period or theme of United States history or culture; or
• Represents a significant, distinctive and exceptional entity whose components may lack individual
distinction but that collectively form an entity of exceptional historical, artistic or cultural significance
(e.g., an historic district with national significance), or
• Outstandingly commemorates or illustrates a way of life or culture; or,
• Have yielded or may yield information of major importance by revealing or by shedding light upon
periods or themes of United States history or culture.
Collections Projects
The application must describe and document the national significance of the collection using the
definition of "National Significance" listed above.
Historic Property Projects
The historic property will be considered to be nationally significant according to the definition of
"National Significance" listed above if it meets one of the following criteria:
• Designated as a National Historic Landmark or located within and contributing to a historic district that
is designated as a National Historic Landmark District.
• Listed in the National Register of Historic Places for national significance or located within and
contributing to a historic district that is listed in the National Register for its national significance.
Please note that properties can be listed in the National Register for significance at the local, state, or
national level; most properties are not listed for national significance. The level of significance can be
found in Section 3 - State/Federal Agency Certification of the property's approved National Register
nomination.
Questions about listing in the National Register of Historic Places, levels of significance in such listings,
and contributing buildings in historic districts should be addressed to the State Historic Preservation
Office for the state in which the property is located
http://www.nps.gov/history/hps/treasures/national.htm