134 



II. P. CAIN — GEOLOGY OF THE WICHITA MOUNTAINS 



The}'' are best displayed on the north side of the mountains, but sweep 

 around the eastern end. and are found so far west as Signal mountain on 

 the south side. Beyond this point they seem to be buried beneath later 

 material. 



The Quana granite, so named from a prominent chief, near whose 

 lodge it is well exposed, is eruptive, cutting the porphyry and the gabbro 

 at many points and exhibiting all the usual contact phenomena. A 

 great dike of granite running from mount Scott north has disturbed and 

 metamorphosed both the porphyry and the limestone, proving that the 

 granite is later in age than either. Additional proof is found in certain 



'^■r^/f. 



Piquke 4. — General View of Granite Hills of the South Range near Quanas. 



Looking south. 



beds, called here the Geronimo series, east of Cache creek, near Fort Sill. 

 In some mesas nearly east of Fort Sill agency, there is a series of sandy 

 shales capped by limestone. These are east of the Fort Sill limestone 

 quarries and from the dip presumably represent a higher horizon. The 

 shales include a conglomerate bed which shows fragments of the pre- 

 existing limestone, porphyry, and granite. They belong accordingly to 

 a series later than the Ordovician, already described. The age of the 

 series is not certain, but its appearance suggests Paleozoic. 



There is a series of dikes of fine-grained greenstone of as } 7 et unde- 

 termined character, which cuts granite, gabbro, and porphyry alike. 



