44 C. Schuchert — Russian Carboniferous and Permian. 



not discussed, these being left to Prof. James Ferrin Smith. 

 In regard to the stratigraphic and evolutional conclusions 

 attained by the author, he states : 



" The views here presented are proved partly by ontogenetic, 

 partly by phylogenetic examinations and observations, and there- 

 fore they may to a certain extent be depended upon. I must, 

 however, note the assumption on my part that the Sicilian 

 Fusulina-limestone is older than the Artinsk [=Permo-Carb. 

 of the Russians] horizon, and again that the latter is older 

 than the Productus-limestone of the Salt Range. By follow- 

 ing out this assumption and comparing the various suture lines 

 with one another, I obtained positive results which were proved 

 by the development of the suture lines of M. orbignyana. 

 This especially applies to the divisions of the external saddles " 

 (p. 354). 



" In this connection I would [first] like to point to an observa- 

 tion, which in spite of its scantiness permits of wholly unsur- 

 mised deductions regarding the climatic conditions at the close 

 of Paleozoic and the beginning of Mesozoic time. In an earlier 

 work I had the opportunity of propounding the question — Is 

 the abundant appearance of Productus possibly connected 

 with a cooler temperature of the sea-water?" [In JSTeues Jahr- 

 buch, 1896, II, p. 86, this problem is stated as follows : " In 

 India at least, but more particularly in the Salt Range, there 

 was a glacial period at the beginning of Permian time. It 

 would be interesting to examine the evidence to see if the 

 great abundance of Produetus has any connection with the 

 cooler temperature of the sea-water."] 



" A greater knowledge of the Paleozoic deposits of the Salt 

 Range has given undoubted evidence of the existence of a 

 Glacial Period at the beginning of Permian time, which 

 deposits locally w T ere laid down in the sea. [For a full bib- 

 liography and a good description of the late Paleozoic glaciation 

 of India, see Noetling, Neues Jahrb., 1896, II, pp. 61-86.] In 

 other words, this sea must have been one with a low temperature. 

 Subsequently, in this sea was deposited the Productus-limestone, 

 and the conclusion is not probable that the temperature of the 

 water rose during the melting of the glaciers and the introduction 

 of the Productus-i&xm&. In the Salt Range, therefore, this 

 fauna is to be regarded as an arctic one. 



u The studies of Medlioottia have shown that M. primas 

 Waag. is in all probability to be regarded as a descendant of 

 M. orbignyanus Vera, sp. of the Artinsk horizon. One can 

 picture to himself the condition whereby the Medlicottias 

 migrated from north to south (more correctly from northwest 

 to southeast) at the same time that they passed into higher beds. 



