The Russian Carboniferous and Permian compared with those of India and America : a review and discussion / by Charles Schuchert.
- Charles Schuchert
- Date:
- 1906
Licence: In copyright
Credit: The Russian Carboniferous and Permian compared with those of India and America : a review and discussion / by Charles Schuchert. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![Because of the wide distribution of the remarkable fish Helicoprion 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 J 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 :— “ What relation the zone with Otoceras woodwardi and Ophioceras 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.](https://iiif.wellcomecollection.org/image/b22407194_0012.jp2/full/800%2C/0/default.jpg)
