PENNSYLVANIC-PERMIC PERIOD 565 



"clearly indicative of a stage at least very high in the Upper Carbonifer- 

 ous (Pennsylvanic). Nearly all the species have been reported from 

 either the Permian of Europe or the Dunkard formation of the United 

 States. . . . Yet the small flora from Onaga [Wabaunsee stage] 

 contains none of the special types or characteristic Permian forms which 

 are present in the Dnnkard, and on account of which the greater part of 

 the Dnnkard is regarded as Permian" (ibid., 115). Judging from the 

 evidence furnished by the invertebrates, this formation is best left in the 

 Pennsylvanic system. 



In the Eocky Mountain region the late Pottsvillian faunas everywhere 

 appear to have been followed by an erosion or land interval. How long 

 this emergence persisted can not as yet be estimated, but the Mississippian 

 sea, with its well known Missourian fauna, apparently reentered the Eocky 

 Mountain area long before the close of the Pennsylvanic, and then, under 

 practically the same physical conditions as those of the Mississippi valley, 

 continued well into the "Permo-Carboniferous" or Oklahomian epoch. 

 The Californian sea extended east into the Cordilleran region to the west 

 of a land barrier, and late in the Pennsylvanic almost united with the 

 Mississippian sea. Both marine areas then persisted independently into 

 Oklahomian time, but the Pacific waters in the Sonoran sea continued 

 long after the Mississippian sea had vanished in red beds and gypsum 

 deposits. The spread of these waters will now be taken up in greater 

 detail. 



According to Cross, 186 the Hermosa formation of limestones, shales, and 

 sandstones occurs in southwestern Colorado, with a maximum thickness of 

 2,000 feet. The Molasse is at the bottom of the Hermosa. According to 

 Girty, the fauna "is probably older than the 'Upper Coal Measures' faunas 

 of the Kansas and Nebraska sections." Nearly all the forms are those of 

 the Mississippi valley. Some of these are: Triticites secalicus, Clicetetes 

 milleporaceus, Prismopora serrata, MeeJcella striaticostata, Chonetes meso- 

 lobus, Productus cora, P. punctatus, P. nebrascensis, Marginifera wabash- 

 ensis, Spirifer rochymontanus, S. cameratus, Squamularia perplexa, Spi- 

 riferina campestris, Composita subtilita, Myalina subquadrata, Bellero- 

 plwn crassus, Pat ell ostium montfortianum, Eupliemus nodocarinatus, and 

 Phillipsia major. 



At Moab, Utah, and in Sinbad valley, on the Colorado-Utah line, 

 Girty 187 has also determined Syringopora multattenuata, Lophophyllum 

 profundum, Campopliyllum torquium, Axophyllum rude, Enteletes hemi- 



186 Cross : Folios 120, 130, 131, and 153, U. S. Geological Survey. 



187 Girty in Cross : Journal of Geology, 1907, pp. 668-676. 



