Badlands at the foot of Scotts Bluff's north face.
Courtesy, Union Pacific Railroad.
Natural History of Scotts Bluff
Although Scotts Bluff is primarily significant
because of its historical associations, its geology and biology are also
interesting. Indeed, appreciation of the history of the bluff is
enhanced by an understanding of how this bluff was formed and how it
influenced migration routes. An elementary knowledge of the plant and
animal life of the area, which is today much as it was in the covered
wagon era, adds to your understanding of this story.
Elevations. The highest point in the monument
area is South Bluff, 4,692 feet above sea level. (The highest point in
Nebraska, more than 5,000 feet, is in Banner County, south of Scotts
Bluff.) The "high point" on Scotts Bluff proper is 4,649 feet,
which is 766 feet above the North Platte River or 700 feet above the
badlands at its immediate base. The elevation of monument headquarters
is 4,114 feet.
Geology. This bluff, like the neighboring
Wildcat Hills, Chimney Rock, and Courthouse Rock, is an erosional
remnant of the ancient Great Plains. These plains were formed by the
deposit of gravel, sand, and silt brought down by rivers from the Rocky
Mountains after they were uplifted about 60 million years ago. At
intervals, 30 to 40 million years ago, volcanoes to the west also added
great quantities of ash and dust deposits. When the process of deposit
slowed, erosion gained headway, cutting new river valleys in the Plains.
High tablelands were left on both sides of the North Platte Valley.
Landmarks such as Scotts Bluff and Chimney Rock have hard rock caps that
protect them from erosion.
The lower two-thirds of the bluff consists of Brule
clay, an Oligocene deposit of buff-colored, soft-textured sandy clay.
The badlands formation at the foot of the bluff dramatically
demonstrates the rapid erosion of the Brule clay when unprotected by cap
rock. The upper one-third of the bluff consists of the Arickaree
formation, gray sand beds of the Miocene Epoch. The uppermost Arickaree
beds form the top surface of the bluff. These are laced with hard
tubular concretions which help protect the bluff and add to the
resistance of the beds to weathering. All the formations exposed in the
walls of the bluff are interspersed with thin layers of pinkish volcanic
ash.
Titanothere skull from the fossil collection, Oregon Trail
Museum.
Paleontology. The Badlands regions of western
Nebraska and South Dakota have become world famous for their extensive
deposits of fossils of mammals and other animals that lived during the
Oligocene and Miocene Epochs of the Cenozoic Era. The Brule clay
formation of Scotts Bluff and vicinity is particularly rich in fossil
remains of extinct animals of Oligocene age, 30 to 40 million years
ago. These exposed remains gave rise to many Indian legends and were
frequently noted by curious emigrants. Scientists from many institutions
of learning have continued to explore and examine these fossils since
1847, when Dr. Hiram Prout of St. Louis described a jawbone brought to
him by a fur trader as that of a Titanothere, a giant
rhinoceros-like creature.
Among the most common fossils of the Scotts Bluff
vicinity, now in the collections of the Oregon Trail Museum, are giant
turtles, pig-like Oreodonts, ancient forms of rhinoceroses
saber-toothed tigers, dogs, deer, camels, and rodents. The horse family
is represented here by Mesohippus, a three-toed creature about 18
inches in height.
Yucca in bloom at the summit of Scotts Bluff.
Plantlife. The conspicuous trees on the summit
and north slopes of Scotts Bluff are ponderosa pine and a juniper
usually called Rocky Mountain red cedar. In ravines and along the river
banks are cottonwood, willow, and boxelder. The most common shrubs in
the area are mountain-mahogany, wild currant, and wild rose. Wildflowers
include sunflower, daisies, wild sweetpea, golden banner, penstemon,
Indian paintbrush, yucca or soapweed, ball cactus, and prickly pear
cactus. The dominant grasses are blue grama, side-oats grama,
buffalo-grass, slender and western wheatgrasses, and woolly sedge.
Wildlife. During historic times the North
Platte Valley was in the heart of buffalo country, but extermination in
the 1870's brought an end to the era of the wild buffalo (bison), which
had been the staff of life to the Plains Indians and the main food
supply on the white man's frontier. A small captive herd of bison is
preserved today in nearby Wildcat Hills State Park. The bighorn and the
grizzly, described by early travelers, disappeared by 1860, leaving an
occasional rare skull as their last testament. The pronghorn (antelope)
is still common in the tablelands north and south of Scotts Bluff, but
deer are the only large hoofed animals which still frequent the monument
area. Other survivors include red fox, coyote, raccoon, porcupine,
badger, beaver, muskrat, and fox squirrel. Prairie dogs, once abundant,
have virtually disappeared.
There is a wide variety of bird life. Some of the
species that have been seen at Scotts Bluff aredouble-crested
cormorant, great blue heron, black-crowned night heron, mallard,
green-winged and blue-winged teal, American merganser, turkey vulture,
red-tailed hawk, golden eagle, sparrow hawk, killdeer, spotted
sandpiper, Franklin's gull, mourning dove, great horned owl, (western)
burrowing owl, western kingbird, horned lark, cliff swallow, American
magpie, rock wren, mockingbird, mountain bluebird, Townsend's solitaire,
logger head shrike, western meadowlark, and spotted towhee junco.
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