28 University of Texas Bulletin 



CORRELATION WITH EUROPEAN AND ASIATIC BEDS 



The main marine lower Permian beds of Europe, in which am- 

 monoids have been found, are the Sosio beds of Sicily; the Trogkofel 

 beds of the Carnian Alps, and the Karawanken; the sandstones of 

 Mrzla-Vodica in Croatia ; the beds of St. Girons in the Pyrenees ; and 

 perhaps the cherty beds of Spitzbergen and Barent Island ; the Artinsk 

 beds of eastern European Russia. Of all these the Sicilian Sosio beds 

 are by far the richest, containing twenty genera and subgenera, with 

 sixty-eight species of ammonoids; while the next richest fauna, that 

 of the cephalopod-bearing strata of the Artinsk in Russia, has four- 

 teen genera with forty-two species of ammonoids (not counting the 

 species which have been cited but not described, or which are 

 doubtful). 



It has been the opinion of most of the authors that the cephalopod- 

 bearing Artinsk is a little older than the Sicilian Sosio beds. Karpin- 

 sky gives a short comparison of the faunas and reaches the conclusion 

 that the Sicilian fauna is a little younger, but that it is very similar 

 to that of the Artinsk; that one form even is identical, while others 

 are very nearly related. He adds that the occurrence of the complicated 

 Arcestidae (JVaagenoceras and Hyattoceras) could be explained if 

 one supposed that such forms belong to more southern regions. 



It appears to me that Karpinsky has paid more attention to the sim- 

 ilarity of the two faunas than to the discrepancies. I do not give much 

 importance to the circumstance that the species are not identical in 

 both faunas, because it is not to be supposed that many forms could 

 have such an enormously wide distribution without undergoing speci- 

 fic changes. Much more important seems to me the occurrence of the 

 same subgenera or genera and also of groups of species wherever 

 these have not been united into special subgenera. Karpinsky tries 

 to demonstrate that practically the greatest part of the Artinskian 

 fauna is autochthonic because their ancestors were living in the upper 

 Carboniferous of Russia. This appears to be a very dangerous pro- 

 ceeding, because if we apply this rule to American occurrences, we can 

 easily show that those ancestors lived in America also in the Carboni- 

 ferous. I do not believe that it is often possible to prove in what spec- 

 ial place on the earth a certain genus originated. Our knowledge of 

 the distribution of ammonoids is far too limited yet, and every day 



