704 SCHUCHERT AND TWENHOFEL ORDOVICIC-SILURIC SECTION 



James, which are literally filled with large corals and Beatricea. Here 

 an additional 40 feet was measured. This gives these lower divisions a 

 thickness of at least 145 feet. 



Zone Cii. South shore. The lower half of this zone is a coral reef of 

 Zaphrentis (8 inches long), Stromatopora, Favosites gothlandicus, Holy- 

 sites catenulatus, Heliolites (?) exiguus, and H. (?) afflnis. Above the" 

 reef occur Platystrophia hiforata, Glitambonites diver sus, Leptcena rhom- 

 loidalis, Schuchertella peden, Parastrophia reversa, etcetera. 



Correlations. — An analysis of the faunules in zones C^ to 0^ clearly 

 shows that they have still the Eichmondian aspect^ for many of the spe- 

 cies are derived from Division B. Some of the new forms introduced 

 here as Dinorthis porcata (second occurrence), Leptcena rhomb oidalisy 

 and Parastrophia reversa are also of this aspect. On the other hand, a 

 new character is given this higher Eichmondian fauna by the appearance 

 of Stromatopora, Haly sites ^ a greater abundance of Heliolites (?), 

 Platystrophia hiforata (European stock), P. cf. reversata, Orthis lauren- 

 tina, 0. flahellites, 0. cf. davidsoni, Schuchertella pecten, RhyncJionella 

 ( ?) janea, Atrypa marginalis, and Hindella umbonata — forms indicating 

 the nearness of Siluric time. No fauna like this is known in the Missis- 

 sippian sea, and it falls in between the time of the highest Eichmondian 

 and the fossiliferous Medina formations of the United States. 



The Ellis Bay formation closes the Ordovicic as in general use, or the 

 Cincinnatic as recently defined by the senior author.^'^ 



SILURIC SYSTEM. NIAGARAN (ANTICOSTIAN) SERIES 



Gerieral discussion of the series. — Billings, in his work on the strata of 

 Anticosti, drew the line that he thought separated the Ordovicic from the 

 Siluric at the top of his Division B. In the preceding pages it has been 

 shown that all of Eichardson's zones, from Cj to 0^, inclusive, retain the 

 Eichmondian fauna of Division B, but that to the fauna of these zones 

 are added a number of corals and brachiopods either persisting into the 

 Siluric or forms transitional in development between the Eichmondian 

 and Clinton faunas. The Eichmondian aspect of the fauna of Division 

 C is clearly maintained throughout to the close of Cg, and even through 

 Cio and Cii, but in the final 15 feet of the two last named zones nearly 

 all of the Ellis Bay fauna characteristic of this formation vanishes, and 

 only a meager biota of Siluric species persists into the next higher Becsie 

 Eiver formation. The writers have, therefore, removed the greater part 

 of Division C from the Anticosti group as defined by Billings, and drawn 



1' Schnchert : Bulletin of the Geological Society of America, vol. 20, 1910, pp. 487-489. 



