PENNSYLVANIA AND DEPOSITS THEREIN. 



65 



Fig. 7 shows the top of the Upper Indian Hollozv Sands, hori- 

 zontally bedded, and underlying the Clarendon Gravels. Such a 

 deposition of coarse gravel with interbedded quicksand on sands 

 could not have been made in an area of scour. This association, like 

 the thinning out of the lozver sands, just noted, indicates that the 

 quiet area of Indian Hollow was crossed by a current of less than 

 8 inches per second ; while at the surface of the ponding, 200 feet 

 above, passed a current of over 30 inches per second, carrying the 

 gravel. 



Fig. 8 show'S more of the southw^est face of the working in the 

 gravel bar. The sand stratum shows that the dip was the same as 

 the average of the beds of the lozver sands, and foreset in the direc- 

 tion of Barnes. The view of the houses of Warren, across the 

 Conewango, in the left foreground, indicates the nearness of the bar 

 to the valley trough, and that it is 200 feet, or more, above it. 



Fig. 9. Clarendon gravels on top of Upper Indian Hollow Sands, East Warren. 



The southern face of the working in this bar is shown in the 

 frontispiece and in Fig. 9. The oil-well rig in the former is the same 

 shown on the extreme left of the latter, and in Fig. 5. This well, 

 and the others in the Hollow, have given a comprehensive idea of 



PROC. AMER. PHIL. SOC, VOL. I.IX, E, MAR. 22, I920. 



