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sediment that filled the drainage systems was sediment that was formerly stored on slopes in <br />the Pleistocene soil and stabilized by vegetation; the deposits filled the Late Pleistocene <br />dissections. Present day Timberlake Creek just below the confluence of its east and west <br />forks provides a close analogy, although the source of excess sediment is Paleocene alluvium_ <br />The early alluvial deposits are well indurated — they were weathered during the same <br />interval as the lower series aeolian deposits — and are braided in character, which gives the <br />deposit the overall appearance of thin laminae. Many important Paleoindian sites — Hellgap, <br />Agate Basin, and Colby in Wyoming, Indian Creek in Montana, Hudson- Meng in Nebraska, <br />and Barger Gulch in Middle Park of Colorado, to name a few — are in these deposits. These <br />deposits started to incise after 6500 years ago and incision continued until about 4500 years <br />ago. On many ephemeral drainages the early set of alluvium and the first incision are still the <br />main features since subsequent incision removed unconsolidated sediment within the <br />incision. <br />The middle unit was deposited between about 4500 and 2800 years ago, almost <br />entirely within the incision formed in the previous 2000 years; some over bank deposits are <br />related to the interval on larger ephemeral streams but are not extensive. The deposit is <br />relatively unconsolidated compared to older alluvium, as are subsequent alluvial deposits. <br />Incision ensued between about 2800 to 1000 years ago, again in the channel formed in the <br />middle Holocene, with a following set of deposits after 1000 years ago down to about 500 <br />years ago. Incision related to the Little Ice Age occurred between 500 and 300 years ago. On <br />small ephemeral drains, the post 4500 alluvial fill (normally mixed with aeolian deposits) are <br />still present (Miller 1992, in prep.). <br />Vegetation is upper Sonoran, dominated by sagebrush (Chrysothamnus spp.) and <br />various grasses. Ground visibility was about 40 percent. Prickly pear cactus, arrowleaf <br />balsam root, biscuit root, Indian paintbrush, tumbling mustard, daisies, Phlox spp., loco <br />weed, and globe mallow also inhabit the area. Biscuit root and tumbling mustard were used <br />prehistorically as food plants, and arrowleaf balsam root for medicinal applications. There <br />are no real riparian habitats except along Timberlake Creek and its main tributaries. Present <br />day land use within the project boundaries is primarily energy development, grazing, and <br />ranching. <br />Fauna in the inventory area can include mule deer, elk, coyote, and black bear, along <br />with cottontail rabbits and various rodents. Mountain lion, bobcat, fox, skunk, badger, and <br />weasel are also present. Bird species observed in the area include the jay, raven, red - shafted <br />flicker, long -eared owl, golden eagle and various other raptors. Present land use in the <br />project area includes ranching, livestock grazing, and big -game hunting. <br />Climatically, the region is characterized as having a cool, semiarid, steppe -type <br />climate. Average annual rainfall ranges between 12 and .16 inches. Temperatures have <br />varied between -20 degrees Fahrenheit in winter and 90 degrees Fahrenheit in summer with a <br />3 <br />