36 C. Schuchert — Russian Carboniferous and Permian. 



Because of the wide distribution of the remarkable fish 

 Ilelicoprion in North America,* Japan, India, and Australia, 

 and of the fact that in the Ural all the specimens of this genus 

 are from the Artinsk horizon, Tschernyschew holds that these 

 data should be given great weight, since so peculiarly constructed 

 an animal " must have had a very restricted duration " ( p. 722 ). 



" According to my judgment all that has been said is strictly 

 against the conclusion of Waagen and his adherents, who see 

 in the Productus-limestone the entire Permian series of Russia. 

 In the general chronological scheme the Productus-limestone 

 has to take a deeper position than that assigned to it by Waagen, 

 Noetling, and others" (p. 725). 



Regarding Noetling's statement that the Productus-limestone 

 passes without break into the Ceratite-bearing beds of the Tri- 

 assic, Tschernyschew admits it to be " a very serious argument 

 in favor of the intimate stratigraphic connection between the 

 Trias and the Permian in the Salt Range, and the entire question 

 relative to the discordance or transgressive nature of the beds 

 appears to him [ Noetling ] impossible in such close association. " 

 Tschernyschew answers that the total dissimilarities in the faunas 

 of the Productus-limestone and the Ceratite beds of the Tri- 

 assic, which are separated by only a few meters ( in fact not a 

 single species passing from one into the other, according to 

 Waagen ), cannot be accounted for, as Noetling thinks, by the 

 changeable nature of the sediments at this level. " Such a 

 sharp paleontological boundary is, rather, testimony for a trans- 

 gressive superposition of the Trias on the Paleozoic of the Salt 

 Range." He then states that numerous Paleozoic and Meso- 

 zoic examples of supposed continuity, with very similar litho- 

 logic deposits, were later shown by the Russian geologists to 

 be discontinuous and transgressive, with great chronologic 

 differences. "With this I shall allow the matter to rest, add- 

 ing the further statement that I believe the evidence cited by 

 Noetling not to have the strength of sound proof in favor of a 

 gradual replacement of the Permian sea in the Salt Range by 

 the Trias, the sharp paleontologic boundary between these 

 deposits indicating, rather, a transgressive superposition of the 

 Scythian stage upon the Productus-limestone" (pp. 726-27). 



As the Otoceras beds of the Himalaya, supposed to be tran- 

 sitional between the Productus-limestone and the Ceratites 

 beds of the Salt Range, enter largely into the question whether 

 the latter are not transgressive upon the former, Tschernyschew 

 discusses the matter as follows : — 



u What relation the zone with Otoceras woodwardi and 

 Ophioeeras tibeticum in the Himalaya bears to the section of 



* This genus is unknown in North America, and the author probably has 

 reference to the related type Campyloprion lecontei occurring in Nevada. 

 See Eastman, Amer. Nat., June, 1905, pp. 405-409. 





