Five rock bodies and four major erosional surfaces are recognized in the subsurface; these are a lower till Kansan(?), a middle till Tazewell(?), a middle silt, an upper till (Cary), and a complexly interconnecting sand and gravel body. Erosion surfaces occur at the top of each rock body. The lower till is confined to the Squaw Buried Valley where it reaches a maximum thickness of 100 feet. The middle till averages 40 feet in thickness but ranges from 100 feet in buried valleys to absent over bedrock topographic highs. The middle silt is largely confined to the Squaw Buried Valley where it reaches thicknesses of 60 feet. The Cary till mantles the area, reaching thicknesses of over 100 feet in bedrock valleys and thinning to less than 25 fee...