SOUTHERN DRAINAGE 217 



the northern outlet was obstructed by what would be called Kansan ice? 

 Upon this light is shed by study of the high-level glacial terrace deposits 

 in the Conewango and Allegheny valleys east of Warren. 



1. It is evident that the low portion of the High Terrace deposits in 

 East-Warren just above Indian Hollow, as well as the lower portions of 

 the deposits at Clarendon, were in still water, for in both cases they con- 

 sist of fine sand and blue clay, while the upper portions are of coarse 

 gravel, with occasional pebbles of considerable size, indicating a current 

 of considerable velocity. The elevation of the summit of the gravel ter- 

 race in East-Warren is 250 feet above the present level of the river. 



2. But most significant of all is the occurrence of a gravel terrace of 

 equal height, beginning at the golf grounds southeast of Warren and 

 running about a mile southeast, up the Allegheny Valley to the mouth of 

 Glade Eun, nearly opposite the old northern opening of Tionesta Creek 

 into the Allegheny, and pointing directly to it. This terrace diminishes 

 in height and width toward the southeast, but at its termination contains 

 many large angular rock fragments which must have been brought in by 

 floating ice. It is evident that this was deposited by a powerful stream 

 making for the Tionesta outlet. 



3. Concerning the deposits farther south in the Tionesta outlet. Prof. 

 E. H. Williams gives me the following facts : 



"The Clarendon gravels are three moraines running north 38° 30' east. The 

 largest has its crest east of the saddle between Warren and Clarendon, so that 

 a stream which could carry gravel to Clarendon would find a down grade 

 thence through Tiona, Sheffield, Barnes, and the Tionesta River to the Alle- 

 gheny. 



"The above crest is 1,110 feet west of Clarendon station. The second and 

 parallel moraine is the slightest and rises but a few feet above the cranberry 

 bog. It is 100 feet broad and its crest is 660 feet east of the station. It has 

 been used as a road-bed across the bog. The third moraine has its edge 920 

 feet east of the station. It is 360 feet broad, and its height on the south side 

 of the track is 8, and on the north side 10 feet above the railroad track. 



"The material of the greatest (western) moraine is mostly local. The 

 foreign material is but one in from one thousand to ten thousand. The crys- 

 tallines are like the high level East Warren gravels, and the fossiliferous part 

 like the low level South Warren gravels. The moraines are water-laid. The 

 matrix on the valley sides is a sandy clay, so plastic that it will ball slightly ; 

 that in the center has been levitated and is sandy. The crystalline and foreign 

 part is more concentrated in the center ; the valley sides are more mixed with 

 slope wash. 



"Now, here is the point I wish to make. It is down grade from Clarendon 

 through Tiona and Sheffield to Barnes and thence down the Tionesta. If there 

 were a clear channel from Warren to Clarendon — as the latter is over the 

 saddle from the former — any material delivered by water at Clarendon must 



