8 - Geologic Investigations

Abstract

This chapter explains the geological investigations carried out at the Horner site during the period 1977–1980. Several geologic investigations were carried out in conjunction with the archaeological excavations of the Horner site in 1949 and 1950 by Princeton University. The results of John Moss's work at the Horner site were never published. The Horner site is situated on the Cody Terrace (Pleistocene), one of a series of terraces contained within the valley of the Shoshone River. An understanding of the terrace system is a necessity for interpreting the geologic setting at the site, which in turn has a direct bearing on the archaeological interpretations. The first known Paleoindian occupation took place around 10,000 years ago, when fine-grained sediment was just starting to accumulate atop the Cody Terrace gravels. The coarse gravels of the Cody Terrace are covered by a thin veneer of sands and clays of Late Pleistocene and Holocene age. The archaeological materials uncovered during the 1949, 1950, and 1952 excavations by Princeton University were contained within the finer grained sediments that overlie the gravels. The configuration of the landscape undoubtedly had an influence on the hunting strategies of Paleoindians. In the immediate vicinity of the Horner site, the gravels have been penetrated to only shallow depths by geologic profile trenches and backhoe trenches. If the Horner site was the locus of a bison procurement area, other buried sites could exist in adjacent areas. From a geologic viewpoint, there are no obvious factors that would preclude their preservation. From the evidence at hand, it appears that at the time the bison bone bed was created, the Cody Terrace gravels were exposed to the surface over most of the area. There may have been some ephemeral stream sediment within the main channel located to the north, but there is no evidence to prove it. A soil is developed in the silt bed that directly overlies the bone bed. The only available database that concerns the archaeological horizons and their geologic context at the Princeton University, Horner I site excavations, are the unpublished reports of Judson (1950) and Schullinger (1951).