NORTH AMERICA AND THEIR VERTEBRATE FAUNA. 



59 



probably not far from its correct faunal correlation as well. The paleontological 

 comparisons are yet to be worked out. The unconformity above the Capitan lime- 

 stone, and locally even in the Delaware Mountain formation, the Capitan having 

 been carried away, is not taken into account in making these comparisons.'^ It is 

 probable that it diminishes rapidly to the northward, where it is of less consequence. 

 "One of the most interesting features of the Guadalupian fauna is its isolation. 

 As has been stated by Girty, the fauna is a unique one, and, as a unit, is now known 

 from no other part of the western hemisphere. At first thought it seems peculiar 



Fig II —Map showing Beede's idea of the Paleogeography of the Red Beds in the southern part 



of the Plain Province. (After Beede.) 



that more of its members were not distributed over the adjacent regions where con- 

 temporaneous strata occur. Their absence in such rocks has been a serious difficulty 

 in any attempt to correlate them with other American faunas. 



"In the first place, the lower Red Beds lying to the eastward, with which the 

 Guadalupian limestones are probably contemporaneous, are believed by some to be 

 to a considerable extent of subaerial origin, while the temporary seas that occupied 

 portions of it from time to time were too concentrated in salt content for normal 



» Richardson, University Mineral Survey Texas, Bull. 9, pp. 43. 44. 1904- 



