AIN-50-21 - Bear Creek to south. 17 to 18 ; - Clay bed in Middle Dakota follows along between 17 & 18, crops out in very few places. Locally it appears to be at least 10' thick and at other places it is clearly cut by channels in which ss above is deposited. Thickness is highly variable - grade unknown, would take prospect pits. 19 Lower Dakota peels back over crest for short distance and shaly-silty parting - represents main clay bed and rider - cuts down for short distance not recorded on photo down AIN-49-08 - South half of Morrison - Turkey Creek hogback 20 A Zone of main clay bed peels back over here and from here south to 21 is represented chiefly by silty ss with clay pellets, or silty zone, or is cut out completely. B. Plotey ss comes in under ledge of first Glencoe sand, locally some silty shale & shaly siltstone between it and base of 1st Glen. 21 Here the shale bed above main one comes in at crest & cap of hogback is about at top of Dakota; The shale pinch outs locally, comes in again at swale at 22. Main clay bed out all along here 22 Swale where clay above main bed in for short distance 23 Shale above main bed in again & peels down back slope. At some time main clay bed (probably with its split) comes in 25