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CHARLES P. BERKEY AND JESSE E. HYDE 



mediate history. There is little doubt but that the oversteepen- 

 ing, the brecciation, faulting, and some of the mixing of materials 

 of different types were caused by glacial advance involving the 



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Fig. 8. — Photograph of the thin horizontal sand layer cutting inclined assorted 

 sands. Note the cross-bedding in the horizontal layer at the right. See explanatory 

 drawing, Fig. 9 below. Left is northwesterly. 



Fig. 9. — Diagrammatic drawing to accompany photograph of inserted sand layer, 

 Fig. 8. The dotted area indicates the portion shown in Fig. 8. 



whole mass in some way in differential movements. But before 

 that could be accomplished much of the material had to be assorted, 

 and this had been done, as the great variety and excellent sizing 



