REPORT OF THE DIRECTOR I9IO 161 



Correlation with Mississippi basin faunas 



A very striking evidence of the isolation of the southern St Law- 

 rence basin at this time is the want of relationship of the fauna of 

 Nova Scotia and the Magdalen islands, with the faunas of similar 

 age in the Mississippi basin. While the number of species common 

 to the two regions is small, yet careful study reveals several species 

 of very similar characters. This is especially true of species of the 

 genera Edmondia, Liopteria, Productus, Schizodus etc. Indeed some 

 of them are so similar that were one a little incautious in discrim- 

 inating characters they might be considered as identical. 



Productus t e n u i c o s t i f o r m i s is sufficiently like P. 

 tenuicosta that were it larger and more produced anteriorly 

 the two would readily pass as the same species. P. d a w s o n i is 

 also closely related to P. laevicosta and P. ovata. 

 Edmondia sp. is very closely related to E. n i t i d a and to 

 E. quadrata from the Kinderhook, but appears to have the beaks 

 more nearly terminal, and is closely related to E. o b 1 i q u a from 

 the Devonic. Relationships nearly as close occur among the other 

 groups and will be occasionally mentioned under the specific descrip- 

 tions. The general affinities seem to lie with the lower Mississippic. 

 At the same time their rather close relationship to the Devonic 

 pelecypods also makes it apparent that the fauna can not be much 

 farther removed from the Devonic than its relationships with the 

 Mississippi valley faunas would indicate. There seems to be much 

 evidence in the Magdalen islands material to confirm Schuchert's 

 correlation of the beds with the Kinderhook and immediately over- 

 lying beds. • 



THE FAUNA OF CAPE LE TROU, GRINDSTONE ISLAND 



These specimens are mostly preserved as casts in a ferruginous 

 magnesian limestone having the appearance of a brownish sandstone. 



Spirorbis sp. 

 Casts too poorly preserved for identification. 



Rhombopora exilis Dawson? 

 Stenopora exilis Dawson. Acad. Geol, p. 287, fig. 85. 1878. 

 Molds of specimens have the size and form of this species and so 

 far as can be determined, a similar topography. 



Orbiculoidea limata nov. ? 

 (See page 177) 



