THE PORAMINIFERA OF THE BONAVENTURE CHERTS 



OF GASPE 



BY RUFUS MATHER BAGG 



The material here studied from the Bona venture formation con- 

 sists of six thin rock sections of cherts sent to the writer by Dr John 

 M. Clarke. Accompanying these thin sections are a number of 

 excellent microphotographs made by Prof. George H. Hudson of 

 Plattsburg. We acknowledge our indebtedness to Doctor Clarke 

 who has furnished some necessary literature and also to Professor 

 Hudson, whose wonderful skill in photomicrography has assisted us 

 in the identification of species which might otherwise have been 

 overlooked. 



The purpose of this investigation has been not only to determine 

 the existence of this fauna but if possible, the geologic age of these 

 cherts or impure flints, since they naturally are derived from an 

 earlier epoch than the conglomerate in which they are found. The 

 Bonaventure formation is regarded by Doctor Clarke as largely a 

 gravel deposit of late Devonian or early Carboniferous time. The 

 chert specimens are all filled with Foraminifera, many of which are 

 as perfect as when originally deposited in the ooze of a paleozoic 

 ocean, and the silification of their tests was slow enough to preserve 

 every chamber and septal division. We have identified in these six 

 rock slides seventeen genera and forty-five species belonging to many 

 types, but it is only fair to state that we have by no means exhausted 

 the material. This is because the identification of fossil Foram- 

 inifera in cross section alone is exceedingly difficult. All the study 

 possible after careful and searching investigation fails to give one 

 confidence of the certainty of every species determined. This is 

 especially true of the rotaline forms where tangential sections of 

 different genera are much alike, as, for example, Truncatulina and 

 Anomalina or Pulvinulina; or Verneuilina and Bulimina. This 

 problematical factor must be clearly borne in mind and accounts for 

 the failure to describe additional species which we know to exist in 

 the cherts but which without further material it is hazardous to 

 classify. 



Evidence from Sponges 



There are fortunately a number of other organisms present in the 

 slides beside Foraminifera. The simplest of these consist of uniaxial 

 and tetraxial sponge spicules which occur in some abundance on two 



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