246 PROCEEDINGS OF THE ACADEMY OF [1888. 



idee in the Mesozoic strata of the west : and the genus Anodonta is, 

 if the opinion of Hall is adhered to, represented in the Devonian by 

 two species, but that these two forms really belong to Anodonta is 

 still questioned. Dawson has described several allied forms from 

 the carboniferous of Nova Scotia ; their family position is as yet 

 also unsettled. With these considerations in view, the evidence 

 thus far obtained points to a high antiquity for this group of bivalves 

 which now is so abundantly represented in all our streams and 

 ponds. As will be noted Crustaceans are represented by a species 

 of Cythere ; and a trilobite of which a single pygidium only has 

 been discovered. Vertebrates are rare also, a few fish spines about 

 two centimetres in length, and several teeth, and dermal tubercles 

 are the only remains of this class found. 



