151 



VALVES of Billingsella retroflexa from sandy shale at Young point. 



(The dimensions in this table are in millimetres.) 



Dimensions 

 of others from 

 the sandy 



The greater proportionate width of the dorsal is due chiefly to its 

 shorter umbo. The shells in these shales are proportionately narrower 

 than those in the sandstone bed ; they are also much smaller, but the 

 difference does not seem to be specific. 



Owing to the coarseness of the matrix both in the sandstone and the 

 shales, the finer details of surface ornamentation are obscured. 



OSTRACODA. 



OSTRACODA OP THE BASAL CAMBRIAN ROCKS IN CAPE BRETON. 



' Investigations of the Cambrian rocks in Cape Breton has brought to Peculiarities 

 the writer's notice a number of new types of these small Entomostracans, Q tracoda 

 and with the permission of the Director of the Canadian Geological of the Basal 

 Survey, these were communicated to the Natural History Society of 

 Montreal, (See Can. Rec. Sci., Vol. VIII page 437.) 



