Figure 64— Surface roughened pottery, Class II.
Figure 65— Surface roughened pottery, Class III.
Geology of the LoDaisKa Site[2]
By Chas. B. Hunt
The LoDaisKa (Sanger) Site, about a mile and half south of Morrison, Colorado, is a rockshelter under a projecting ledge of Paleozoic (Pennsylvanian) sandstone that dips steeply east. The pre-ceramic occupation layers at this site are believed to correlate with the Piney Creek alluvium ([Hunt, 1954, p. 114]). The accompanying map ([Fig. 66]) illustrates the general geologic setting of the site; it shows the general distribution of one upper Pleistocene and two Recent units.
The upper Pleistocene unit (Qg on the map) is a bouldery gravel with which is included some variegated, silty and clayey alluvium. This bouldery gravel is exposed in Strain Gulch upstream from the site, and it covers much of the upland northwest of that part of the Gulch. Downstream from the site this bouldery gravel is southeast of the Gulch and forms the high terrace extending from the site to the highway. Because the deposit is bouldery, and because the boulders are little weathered the deposit is assumed to be Wisconsin in age.
The alluvium with variegated colors mapped with this bouldery gravel is exposed in Strain Gulch about 700 feet northeast of the site, and in the tributary from the west that joins Strain Gulch about 200 feet upstream from the highway. In this latter tributary the alluvium rests on strata of Paleozoic age. At both localities the variegated alluvium is overlain by dark-colored, sandy and silty alluvium.
The variegated alluvium has a distinct, lime-enriched zone, probably representing the alluviated layer of an old soil from which the upper layers have been eroded. The lime-zone is comparable in thickness to that found in soils in Wisconsin age in the Denver area. Moreover, at the outcrop in Strain Gulch, the lower part of the alluvium is stained with iron oxide about the way deposits of Wisconsin age are stained in the Denver area. However, the dating of the deposits is uncertain because it has not been established whether the layers enriched in lime and iron are the result of surficial weathering or ground-water action.
Probably, though, these deposits are late Pleistocene in age, and fossils in them probably will include the Pleistocene forms.