PENNSYLVANIAN-PERMIAN GLACIATION 469 



the oldest of those now exposed as well as the youngest contain 

 the pre-Cambrian boulders. 



This difference in constituents of the conglomerates in the two 

 areas is probably due to somewhat different conditions in the two 

 areas which resulted in an earlier uncovering of the pre-Cambrian 

 rocks in the Wichitas than in the Arbuckles. The earlier uncovering 

 of the Wichita pre-Cambrian may have been due to a higher uplift 

 of the Wichitas which resulted in faster erosion, or to a thinner 

 covering of the Paleozoic, or to a combination of both of these 

 conditions. 



GLACIAL ORIGIN OF THE CONGLOMERATES 



Whatever the correlation of these conglomerates it is theip char- 

 acter and their probable origin to which attention is called. The 

 glacial origin of the conglomerates is believed to be indicated by the 

 following characteristics : 



1. The heterogeneous character of the conglomerates, as indi- 

 cated by the range in source of rock material and the great variation 

 in size of the constituents in local deposits. 



2. The non-residuary and unweathered character of the con- 

 stituents of the conglomerate. 



3. The great thickness of the conglomerate beds. 



4. The occurrence of polished and striated surfaces of the rock 

 floor upon which the conglomerate rests, and of polished, striated, 

 and grooved pebbles and boulders in the conglomerate. 



The phenomena described under the first three of these headings 

 are of general occurrence and are everywhere exhibited by the con- 

 glomerate, while the features described under the fourth heading, 

 which seem to indicate distinctive evidences of glaciation, are of more 

 rare occurrence and are not everywhere developed or preserved. 



In addition to the distinctive evidence of glacial origin furnished 

 by the constituents of the conglomerate and the striated rock floors, 

 there are on the flanks of the Arbuckle Mountains U-shaped valleys 

 formed during the period of conglomerate deposition which possess 

 the characteristic form of glacially eroded valleys. One of these 

 U-shaped valleys, that of Honey Creek, has a polished and striated 

 rock floor upon which the typical glacial conglomerate rests. 



