AIN-50-19 (Alameda-Morrison area) 16. Main clay bed continues into this swale from N. but is completely pinched out at south end, the first Glenczirn ss coalescing with overlying sandstones at crest S end swale. As far as can be determined the friable sandstone is either in the Dakota or marks zone of other, little clay beds between it & the Glenczirn Diagrammatic section throu swale. crest hogbo Dakota Frisbie boulde Sandy cl. ? 17. The first sandstone of the Glenczirn changes to a platy, grossly cross bedded unit with intercalated shaly siltstone zones. This weakens unit and is responsible for swale in crest hogback. lst ss main cl. bed horizon 2nd ss 2nd clay 3rd sh. with bout. 15