GEOLOGICAL AND GEOGRAPHICAL DISTRIBUTION. 



In North America Pelycosaurian reinaius have been found in north 

 central Texas, Baylor, Archer, Wilbarger, and Vernon counties, and the 

 adjacent portions of the Indian Tenitory ; New Mexico; noitheastern 

 Oklahoma ; Cowley county, Kansas ; Vermilion county, Illinois, and the 

 vicinity of New London, Prince Edward Island, in Canada. The remains 

 of Pelycosaurs always occur mingled with remains of an abundant fauna 

 composed of fishes, amphibians, and other ordei's of reptiles. The faunae 

 of the different regions show slight but well-marked differences which 

 indicate that there was some difference of distribution in the Permian 

 animals of the continent. 



Beyond the limits of North America Pelycosaurs occur in Bohemia, 

 Naosaunis, and less certainly in central Germany, Cteuosaunis and Anomo- 

 saurus; and in France, Callibrachion and Stereorachis. Pelycosauria do 

 not occur in Africa, and it is improbable that they occur in the Russian 

 deposits. 



There is no locality in which Pelycosaurs occur with Theriodonts, 

 Therocephalians, or Anomodonts. The Theriodontia and Therocephalia are 

 found only in Africa and Russia ; the Pelycosauria only in North America 

 and Central Europe. 



Cotylosaurians occur in North America, Russia, and South Africa, but 

 the families are different. The PariotichidcB are not represented outside of 

 North America and the Cotylosaurians are represented on this continent, if 

 at all, by a single genus and species, Labidosaiirus hamatus Cope ; this 

 animal resembles in general form the Pan'otic/ndo' and may well turn out 

 to be closer to that family than to the Pareiasaurida". 



Stegocephalians of closely related form occur in North America, South 

 Africa, Russia, and India. Their wider distribution is explainable on the 

 basis of their greater antiquity, and the same reason perhaps applies to the 

 wide extension of the Cotylosaiiria. 



The character of the distribution is certainly suggestive of a possible 

 separation of a North American-European land-mass from an African-Asiatic 

 land-mass in the time when the Stegocephalians were predominant and the 

 Cotylosauria were just beginning their great radiation. By the time the 

 specialized Pelycosauria^ Theriodontia^ and Tlicrocephalia began their develop- 

 ment the masses were so far distinct that the groups did not mingle. This 

 is further supported by the development in the North American mass of the 



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