separated the Green River Basin into two parts. Its upward movement was reactivated during
<br />the Tertiary and since then most of the Tertiary -age rocks have been eroded away (Young and
<br />Young 1977: 57). Within the study area the Cretaceous -age sedimentary rocks including
<br />sandstones and shales along with major coal beds of the Williams Fork Formation form the
<br />bedrock.
<br />The study unit lies within the Williams Fork Mountains, which form the divide
<br />between the Yampa River Valley to the north and the Williams Fork Valley to the south.
<br />Buck Peak lies to the northeast. These mountains are heavily dissected by tributary drainages
<br />that flow northeast to the Yampa River and southwest to the Williams Fork River.
<br />Permanent and intermittent drainages occurring near or within the project area include
<br />Jeffway Gulch, Deal Gulch and Spring Gulch, which drain into the Williams Fork River to
<br />the south, and Deacon Gulch, which drains into the Yampa River to the north. The
<br />headwaters of many of these are fed by unnamed springs located throughout the study area.
<br />Soils in the project area include Bulkley silty clay, an alluvium derived from shale
<br />located on hills and alluvial fans (USDA NRCS 2004:43); Foidel loam, found on
<br />mountainsides and formed from loess and colluvium derived from fine grained sandstone and
<br />shale (ibid.:78); Herperus fine sandy loam, located on hills and plateaus and formed from
<br />loess and in alluvium derived from sandstone and shale (ibid.:97-99); Lamphier fine sandy
<br />loam, a colluvium and residuum derived from sandstone found on mountainsides (ibid.:109);
<br />Lamphier-Jerry complex, found on plateaus and mountainsides, with Jerry being formed from
<br />residuum derived from shale (ibid.:110); Morapos loam, located on plateaus and formed from
<br />residuum derived from shale and in loess (ibid.:123, 124); Torriorthents-Rock outcrop,
<br />located on the backslopes of hills and mountainsides with Torriorthents formed from
<br />residuum and colluvium derived from sandstone and shale (ibid.:171); Ustorthents, frigid-
<br />Borolls complex, located on footslopes and backslopes of mountainsides and both formed
<br />from residuum and colluvium derived from sedimentary rocks (ibid.:177); and Winevada-
<br />Spiltro complex located on plateaus and mountainsides and both formed from residuum
<br />derived from sandstone (ibid.:184).
<br />Elevations within the project area range from approximately 6880 to 7640 feet. The
<br />dominant vegetation within the project area is comprised of Transitional Zone brush
<br />including oakbrush, serviceberry, Gamble oak, and chokecherry. Aspen, dogwood, prickly
<br />pear, sagebrush, yarrow, mules ears, manzanita, aster, globe mallow, snap dragons, sego lily,
<br />wild pea, saw grass, thistle, Indian paintbrush, snakeweed, lupine, mint, wild rose, wetland
<br />grasses, and wild sunflower are also present in some parts of the study area. Overall, ground
<br />visibility was poor to moderate. This biome supports a variety of wildlife species. Mule deer,
<br />elk, coyote, and black bear are locally common as are jack rabbits, cottontail rabbits, and
<br />various other rodents. Mountain lion, bobcat, fox, beaver, skunk, badger, and weasel are also
<br />area inhabitants. Observed bird species include the pinyon jay, raven, red -shafted flicker,
<br />red-tailed hawk, golden eagle, bald eagle, and various other raptors.
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