FAUNAL CHARACTERISTICS OF THE SEDIMENTS 353 



Bilohiies hilobus (Linne), Skenidum leivisii (Davidson), and Spirifer 

 crispus (Hisinger). 



Thus faunally both of these zones are of Silurian age and probably 

 not younger than early Niagara or Wenlock. It is not clear in what way 

 they are structurally related to each other. The fossils are too few and 

 too imperfect for determination of close correlation with other known 

 formations. 



Formation III is represented by a considerable number of fossiliferous 

 outcrops containing a rich, purely marine fauna. The lower beds of 

 this formation contain corals, not abundantly but frequent in occurrence, 

 chiefly of the genera Syringopora and Favosites. I have not up to the 

 present stage of my investigation discovered a trace of the genus Holy- 

 sites, although Breger mentions it in his field notes. The following 

 widely distributed species furnish the basis for correlation : 



Atrypa reticularis (Linne), Leptcena rhomboidalis (Wilckens), Spiri- 

 fer crispus (Hisinger), Pentamerus galeatus Dalman, Meristina tumida 

 (Dalman), Wilsonia sp., Cornulites sp., Dalmanites sp. 



Associated with these cosmopolitan types are Spirifer elevatus Dal- 

 man, Strophonella funiculata (McCoy), Leptostropliia filosa (Sowerby), 

 the peculiar form called Avicula danhyi by McCoy, and Monomerella 

 ivoodwardi (Salter), giving a complexion to the fauna unfamiliar to 

 American paleontologists, though characteristic of certain transatlantic 

 Silurian faunas. 



This is the fauna listed by Shaler^ in his paper of 1886 as of the 

 ^'Orange Bay section." It was again reported by me® in 1905 under the 

 station name of "Whiting Bay, ^o. 1440." In the latter list the resem- 

 blance of many of the species to well known Helderbergian species led to 

 a misinterpretation of the correlation of the fauna. Having been strongly 

 impressed by the wide fluctuation of characters of species in the Chapman 

 fauna in northeastern Maine, I then gave too much weight to resem- 

 blances. Recent exhaustive study of the new material has convinced 

 me that in place of having here a mixture of Helderbergian with Xiag- 

 aran forms, w^e are really dealing with a series of transatlantic rather 

 than American faunas. 



Several of the British species have not heretofore been reported in 

 American Paleozoic beds, although closely related forms have appeared 

 in the Helderbergian faunas farther west. The species I listed in 1905 



* Loc. cit, p. 54. 



" G. O. Smith and David Wliite : Ttie geology of tlie Perry Basin in southeastern 

 Maine. U. S. Geological Survey. Professional Paper No. 35, 1905, p. 22. 



