C. Schuchert — Russian Carboniferous and Permian. 153 



Phipidometta, Enteletes, Derbya, Meekella, Semvnula, and 

 Hustedia. On the other hand, this arctic fauna predominates 

 in Productus and Spirifer. Of the former genus the species 

 are nearly all strangers to American paleontologists, since the 

 bilobed or deeply sinused and the abundantly spinose forms 

 are the common ones. The Spirifers also are strange in that 

 hardly any have the plications strongly bundled as in S. cam- 

 eratus, while such little known groups as that represented by 

 8. arcticus and 8. supramosquensis (also recalling 8. neglectus 

 of the Lower Carboniferous) predominate. 



" Ten or more species of Bryozoa are present, of Penestella, 

 Pinnatopora, Goniocladia, and Phomhopora. None, how- 

 ever, can be specifically identified and those of the genus 

 Phombopora are of a type — stout branches from \ to f inch 

 in diameter — unknown in the Mississippi basin. This is also 

 true of Goniocladia. Pelecypoda are all small and rare (5 

 species), and the Gasteropoda (3 species, 4 specimens) almost 

 absent. Not a trace of a cephalopod is present, and this is all 

 the more strange since the Indian Permian has 14 forms of 

 nautiloids and 7 of ammonoids. Nor is there a trace of a 

 trilobite, while the corals are represented by one or two species 

 of cyathophylloids. 



" The work of the United States Geological Survey in Cali- 

 fornia and Alaska is establishing two facts of great value in 

 general geology, namely, that on the west coast of North 

 America there is (1) a great thickness and grand sequence of 

 Carboniferous and Permian strata [between 6000-7000 feet of 

 Permian in Copper River region of Alaska] ; (2) that these 

 have faunae of the Pacific type and not of that of the Missis- 

 sippi basin " (p. 44). 



Conclusions. 



As the great Russian geologist has stated in his introduction 

 that he will be the first to greet friendly criticism " with pleas- 

 ure," the present reviewer takes the opportunity of concluding 

 this long review with the following friendly remarks : — 



1. The foregoing review of the recent work of four excel- 

 lent investigators in the correlation of Carboniferous and Per- 

 mian strata and faunas shows clearly that a final interpretation 

 of the sequence of events closing the Paleozoic is still far from 

 attainment. Further, that while harmony exists regarding the 

 basal zone of the Carboniferous (Upper Carboniferous of most 

 writers), there is as yet no agreement as to the upper limits of 

 this system of rocks and hardly any concerning the delimita- 

 tion and sequence of the Permian. As has been seen, there is 

 little or no difference of opinion in regard to the sequence of 



