PENNSYLVANIAN-PERMIAN GLACIATION 487 



The boulder conglomerates associated with the granite moun- 

 tains in the western part of the Wichitas are largely granite material 

 without appreciable amounts of calcareous cementing constituents 

 and hence in most places are an unconsolidated formation. But 

 where limestone material is abundant in the conglomerate, it is 

 usually a firm consolidated formation. The unconsolidated char- 

 acter of much of the conglomerate composed of igneous rock boul- 

 ders, sand, and clay has led to the suggestion that it may be of a 

 later age than the Permian Red Beds. However, there seems no 

 good reason to doubt the usually accepted correlation stated by 

 Taff^ that the boulder conglomerates at the base of the mountains are 

 of the same age as the red shales and sandstones into which they 

 appear to grade in the surrounding "Red Beds" plains. 



WORK OF OTHERS 



While the data bearing on the problem of Pennsylvanian- 

 Permian glaciation here presented are wholly the work of the writer, 

 it is important to refer to the earlier work of two other geologists 

 who have either ascribed directly or at least suggested the possible 

 glacial origin of certain Permo-Carboniferous deposits within the 

 general region, but outlying some distance from the Arbuckle and 

 Wichita mountain areas. 



J. A. Taff, in 1905^ and in 1909,^ described the occurrence of 

 erratic boulders in shales of Middle Carboniferous age in the Oua- 

 chita Mountains of eastern Oklahoma. The erratic boulders con- 

 sist of various types of rock such as limestone, sandstone and quart- 

 zite, some of which are angular and ranging in size up to 50 feet in 

 diameter. It was Taff's belief that the erratic boulders were ice- 

 borne and derived either from the Arbuckle upKft or from associated 

 areas farther to the south in Texas. 



Taff seems not to have discovered any distinctive evidence of 

 glacial strice on the boulders described by him, and in 1912, J. B. 

 Woodworth,"* after making some investigations, reached the con- 



' J. A. Taff, U.S. Geol. Survey, Professional Paper 31, p. 76. 

 ^ Science, Vol. II (1905), p. 225. 



^ Bull. Geol. Soc. Am., Vol. XX (1909), p. 701; and Science, Vol. XXIX (1909), 

 P-637. 



4 J. B. Woodworth, Bull. Geol. Soc. Am., Vol. XXIII (1912), pp. 457-62. 



