THE FACTS 385 



tus and Spirifer plicatella. There are also several species under special 

 names that represent forms called Spirifer crispus and Spirifer elevatus 

 in the English Wenlock. 



Pentamerus galeatus Dalman is recognized in the Bohemian section, 

 but it does not appear till the fauna F 2 , and though numerous closely 

 related forms of Khynchonella are figured under special names, Rhyn- 

 chonella wilsoni Sowerby is not listed till fauna F 2 . 



It would lead us too far afield to discuss the Barrandean species, but 

 sufficient evidence is given in the species named to show that in the Bo- 

 hemian fauna E 2 , as in the Wenlock faunas of England, are found asso- 

 ciated in the same fauna species which are separate in the two North 

 American Niagara faunas, namely, the Eochester and the Edmunds 

 faunas. 



THE PODOLIAN FAUNAS 



Turning still farther east and south to the government of Podolia, 

 Russia, we discover the, conditions described below, as expressed in the 

 faunas of the three zones of Silurian, called I, II, and III in Wenju- 

 kow's paper.** 



His zone I is correlated with the Wenlock shale of England, the 

 Mergelschiefer und sandstein of Gotland (c), and E e 1 of Bohemia. It 

 contains Orthis elegantula and hybrida, Bilobites biloba, Leptcena trans- 

 versalis, Strophomena rhomb oidalis, Strophonella euglypha, Atrypa 

 reticularis, Spirifer crispus and elevatus, Cyrtia exporrecta, Whitfteldia 

 tumida, Pentamerus galeatus, Rhynchonella sphwrica. 



Several of these species occur also in the zone II, which is correlated 

 with the Wenlock limestone, Lower Ludlow, and Aymestry of the Eng- 

 lish section. 



The species Orthis elegantula, Strophomena rhomboidalis, Chonetes 

 striatella, Atrypa reticularis, Spirifer elevatus, Spirifer crispus, Penta- 

 merus galeatus, and Rhynchonella wilsoni continue upward to the zone 

 III, which is made the equivalent of the Upper Ludlow and reaches up 

 to fauna F 2 of the Bohemian section. 



What is noticeable in this section is the absence of the plicate forms 

 of the radiate spirifers; the prominence of forms of the Spirifer clc- 

 vatus-crispus type; the absence also of the Spirifer sulcatus. A form 

 very closely related to Strophonella funiculata McCoy is named by Wen- 

 jukow Strophonella semiovalis. 



Here is evidence of the predominance throughout this section of the 



8 T. Wenjukow : Die Fauna der Silurischen Ablagerungen des Gouvornnionts Fodollen. 

 St. Petersburg, 1899. 



