Dakota Problem Rock Creek Area Pueblo Co, Colo. Summer 1949 Section of Graneros - # G491 -> G497 Top Ft. | 17 4 Bentonitic shale 59 Weathered brown & gray clay shale, 1" rusty zone at base. Samples 0-43 G491-A1 " 43-59 G491-A2 33 Dark gray fresh clay shale, thin rusty zone at base. Sample full 33 G491-B3 29 Dark gray clay shale. Sample full 29 G491-B4 0 to 10 Concretionary limestone - only locally present. Fossiliferous. (Ammonites Zone A.) Ammonites & Oysters 15 Bentonite & Bentonitic shale 22 Dark gray to black clay shale, 1" concretionary zone with oysters (Oyster zone A) Sample G491-B5 59 Dark gray to black clay shale local and often zone 8" from top "rusty" zone 18" from top 1" bentonite bed at base Sample G491-B6 65 Gray to dark gray clay shale, weathered in upper part 1" bentonite at base, 10" above this is buried 6" rusty zone. Sample G491-B7