REPORT OF THE DIRECTOR IQIO 159 



acter, together with the fact that the other groups common to the 

 rocks of this age are absent, is indicative of the isolation of the basin 

 at the time the rocks were deposited. The absence of the Spirifers 

 and of Chonetes, Derbya, Orthothetes and the hke all point to the 

 same conclusion. 



A general feature of the fauna, especially of the Grindstone 

 island localities, is the extent to which it is dwarfed, the dwarfing 

 being carried even farther than is tlie case with the Nova Scotian 

 fossils. 



Both the Grindstone and Coffin island faunas are related to the 

 " carboniferous limestones " of Nova Scotia, the former the more 

 intimately. The Oyster basin material has 8 species in connnon with 

 the Nova Scotia rocks and the Cape le Trou material has 20 species. 

 The Cape le Trou and Oyster basin rocks have 6 species in common 

 as listed in this paper. Four species are common to both islands 

 and to the Nova Scotia rocks. 



S e r p u 1 a i n f i n i t e s i m a, S t e n o p o r a ? sp., H e m i p - 

 t y c h i n a ? w a a-g e n i , Lingula, Strophalosia, Aviculopinna, 

 Nucula, Pleurophorus ?, S c h i z o d u s d e n y s i , M a r t i n i a 

 glabra, Bucanopsis, Euphemus?, and the Ostracoda are confmed 

 to the Oyster basin locality and horizon. Five of these species are 

 rather common, several specimens of each and more of some of 

 them occurring in the collection. 



The following rather important species, or genera, are represented 

 only in the Cape le Trou collection, the most of them by a number 

 of specimens: Spirorbis sp., Rhombopora exilis?, 

 D i e 1 a s m a s a c c u 1 u s , P r o d u c t u s a u r i c u 1 i s p i n u s , 

 Pugnax, Aviculopecten lyelli, Liopteria, i\I o d i o 1 a 

 p o o 1 i , P a r a 1 1 e 1 i d o n d a w s o n i , E u o m p h a 1 u s 

 exortivus ?, and most of the cephalopods. The striking feat- 

 ure of these comparisons is the fact that so many of the common 

 species at each locality are restricted to that locality and bed. 

 Though the beds are distinct and of somewdiat different composition, 

 yet they are hardly so different as to account for the difference in the 

 faunas contained. There would seem to be a stratigraphic break or 

 a considerable difference in the salinity of the water in which the 

 two beds were laid down. The two localities are about 35 miles 

 apart. 



The species in common are : Beech eria davidsoni?, 

 Orbiculoidea limata, Productus dawsoni, its 

 variety acadicus, P. tenuicostiformis, and O r t h o - 

 c e r a s sp. A. 



