Wilcox, 1982). Early studies considered the deposits as one ash and applied the stratigraphic name "Pearlette ash" to deposits in Meade County, Kansas. Later investigations in Oklahoma, Texas, Nebraska, and Kansas, (Frye et al, 1948), revealed the presence of several ashes of a single middle-Pleistocene age in their study of Great Plains and glacial geologic deposits. They used the ashes as time marker beds to distinguish between Pleistocene and Pliocene deposits. The more recent