THE RELATIONS OF SOME CARBONIFEROUS FAUNAS 21 



do not so strikingly resemble those of the Russian series as is 

 the case with the Hueco faunas. Prodtictus corn is conspicuous 

 by its absence, while if Schzvao-crina occurs at all in the Am- 

 erican section it is in the lower beds associated with Spirifer 

 viarconi and Omfhalotrochus. Indeed, a considerable portion 

 of the faunas of these lower horizons resembles that of the 

 Schzvagerina zone. On the other hand, the highest fauna of 

 all (that obtained near the middle of the Capitan limestone) 

 also resembles the Schwagerina fauna in the number and 

 variety of its Terebratuloids, Spiriferinas, and Spirifers of 

 the type of S. lyra Kut., S. iibctaims Dien., etc., of 

 which S. onexicamts is an American representative. There 

 are few Terebratuloids and Spiriferinas in the faunas of 

 the Hueco Mountains; they are quite different from those 

 of the Capitan limestone, and the Spirifers also are dif- 

 erent. The Product!, especially, of the Hueco faunas are 

 like those of the Schzuagerina zone. Thus, though the lower 

 faunas found in the Hueco Mountains are throughout quite 

 different from the upper ones found in the Guadalupe Moun- 

 tains, both have points of strong resemblance in a common 

 fauna, that of the Schzuagerina zone of eastern Russia. The 

 Russian faunas have peculiarities not found in any of those 

 of the Trans-Pecos region, and of these none is perhaps more 

 striking than the abundance and variety of the Spirifers (espe- 

 cially S. ufensis and S. sufracarhonicus, no representatives of 

 this type being known in Texas), Sfiriferella, Martinia and 

 Martiniopis. Seminula, whose abundance seems to be a dis- 

 tinctive feature of nearly all American Carboniferous faunas, 

 still occurs in numbers in the Trans-Pecos. All the upper beds 

 of the latter, 2,000 feet or more, are characterized by the pres- 

 ence at intervals, often in extraordinary abundance, of a large, 

 greatly elongated Fusulina, F. clongata Shum. And they are 

 marked by the frequent occurrence of large examples of those 

 singular brachiopod genera Leptodus and Richthofenia . These 

 types seem not to occur in the Russian faunas. 



Tschernyschew finds that all the beds whose fauna he dis- 

 cusses, divided by him into zones, of which the highest is the 

 Schzuagerina zone, underlie the typical Permian of Russia. If 



