clay in most places by fairly good sandstone, but at 3 the ss between it & top Gloucery thins to few feet. Appears to be channel filled with clay. Same clay as at 16 (Morrison end), so fairly certain it is mid-Dakota - little flinty zones are clue here. Possibility still exists that this is one of 3 small beds over main bed - possibly the one with the bentonite-like clay further north. As it is not possible to determine this for certain & as ss between this clay & main bed maintains a thickness of 15' to 40' from Morrison south at least as far as Deer Cr., and is the massive x-lam type typical of Dakota, it is reasonable to call it mid- Dakota in south of Golden, whether it is in Golden area or not. Brings up problem, however, of where to place Gloucery-Dakota boundary. 24