GEOLOGICAL SECTION ALONG YUKON-ALASKA BOUNDARY 679 



Graptolites, which are believed to have been found in only three other local- 

 ities in Alaska, Yukon, and the Northwest territories, were obtained at one 

 point. Cambrian fossils were also found at several points, which extends con- 

 siderably our knowledge concerning the Cambrian, as fossil remains of this 

 period have not previously been discovered in Yukon Territory, and in Alaska 

 have been found at but one other locality, over 700 miles to the west. 



Members of the older schistose formations which have heretofore been con- 

 sidered as pre-Devonian, pre-Silurian, or pre-Ordovician were found strati- 

 graphical ly lower than certain limestone beds in which Middle Cambrian fos- 

 sils occur, and are thus of Lower Cambrian or pre-Cambrian age. These 

 schistose rocks are of considerable importance, since they have been shown to 

 be the source of the gold of all the known Yukon placer deposits, as well as a 

 large portion of those of Alaska. 



RED BEDS BETWEEN WICHITA FALLS, TEXAS, AND LAS VEGAS, NEW- 

 MEXICO, IN RELATION TO THEIR VERTEBRATE FAUNA 



BY E. C. CASE 



(Abstract) 



This paper described a trip from Wichita Falls, Texas, across the Permian 

 and Triassic Red Beds of western Texas and eastern New Mexico. A study of 

 the beds was made from where they appear on the east, in close relation with 

 the Pennsylvanian limestone, to where they turn on the flanks of the Rocky 

 Mountains at Las Vegas Hot Springs, in New Mexico. Especial attention was 

 paid to the character of the beds in an attempt to determine the nature of the 

 deposition and the climatic and other changes recorded. The ultimate aim of 

 the study was to determine, so far as possible, the conditions of life and distri- 

 bution of the vertebrate fauna of the so-called Permian Red Beds of north 

 central Texas and adjacent parts of Oklahoma. 



SHINARUMP CONGLOMERATE 

 BY HERBERT E. GREGORY 



(Abstract) 



The Shinarump conglomerate probably constitutes the base of the Triassic 

 in the Colorado Plateau Province, and is separated from the underlying Per- 

 mian by a widespread erosional unconformity. The Shinarump of Powell and 

 Dutton is to be correlated with part of the Lithododendron of Ward, but not 

 with the Dolores conglomerate exposed in southwestern Colorado. 



Discussion 



Dr. A. W. Grabau asked how the Shinarump conglomerate and the limestone 

 conglomerate of the Dolores were formed. 



Professor Gregory replied that there was as yet no satisfactory explanation. 



Mr. N. H. Darton : Regarding the unconformity at the base of the Shina- 

 rump, there was no conclusive evidence one way or the other in exposures near 

 the line of the Santa Fe Railroad. There is an abrupt change in character of 

 sediments and more or less channeling of the surface of the underlying shale. 



