North of Rock River, Wyo, bluffs of Rock Creek in NE 1/4 Sec. 28 T. 22N R. 75W. Top of Thermop. into Mowry starting at thick bentonite. 12. 2.0 - ? Bentonite 11. 5.2 Shale, black fissile with lzmize silt loc, and some thin interbeds siltst and fine gr. SS. 10. 1.3 Sandstone fine gr. + siltstn [illegible] interlean with silty ci5tn. Forms crumbly lodge gray to blue gray yallow blotches. locally has hard resistant SS 0.4+ at loc 9, 1.0 Shale, black fissile 8 0.4 Sandstone scur [illegible] to above, locally hard 7. 0.4 Black shale, silty to shaly with some lite gray sandy ciayen silt 34