732 CHARLES S. PROSSER 



uses the later name of Dyas proposed by Marcou on account 



of the sharply marked separation of the system into two divisions 



in Germany. 



Dr. Freeh's classification of the Upper Paleozoic of Kansas is 



as follows : 



rT „ \ Red shales and clays. 



Upper Dyas j Marion- 



Lower Dyas^J Chase. 

 Transition to Carboniferous 



(distinct line fails.) 



Cottonwood beds. 

 Upper Carboniferous^ Wabaunsee. 1 



Later Dr. Freeh reviewed Professor Cragin's classification of 

 the Permian, and termed the Cimarron series the "Neo-Dyas," 

 and the Big Blue series the " Paleo-Dyas." 2 He stated that the 

 Dyas equaled the Permo-Carboniferous plus the Permian of 

 many authors, and that by general agreement at the St. Peters- 

 burg International Congress of Geologists the names Paleodyas 

 ( = Permo-Carboniferous) and Neodyas (=Zechstein) are em- 

 ployed. 3 



Under the discussion of the boundary line between the Dyas 

 and Carboniferous Dr. Freeh said: The dividing line between 

 the Carboniferous and Dyas formations cannot be drawn with 

 full certainty in every region, since especially in the Dyas the 

 development of the local flora is nearly always the rule, and 

 decisive differences do not exist in the Brachiopod fauna. 



Yet an agreement seems to be gradually forming every- 

 where Where the characteristic Dyas bivalves [Pleu- 



rophoms, Schizodus, Bakewellia, Pseudomonotis) appear in 

 masses (Kansas), there cannot be any doubt about the dividing 

 line. 4 Under the description of the Dyas of the northern hem- 

 isphere and the Arta stage of Russia, as Dr. Freeh prefers to call 

 the Artinsk, he said: That the animal remains of the Permo- 



1 Lethaea -balcEozoica, Bd. II, 2 Lief., 1899, p. 378, as translated above. 



2 Ibid., 3 Lief., 1901, p. 514. 3 Ibid., p. 453 f. 



'■Ibid., pp. 490, 491. I am greatly indebted to Charles W. Mesloh, associate 

 professor of Germanic languages and literatures in the Ohio State University, who 

 very kindly translated for me several pages of Dr. Freeh's description of the Dyas. 



