194 Tertiary Fossils oj Canadat Sfc, 



all common American species. It is curious that in the collections 

 of the Canadian Geological Survey, the group of shells obtained 

 by Mr. Bell and Mr. Richardson in dredging on the north coast 

 of Gaspe in about 60 fathoms, is almost precisely that of these 

 Portland beds. 



On comparison with the St. Lawrence teitiaries, it will be seen 

 that 8 out of 19 species are distinct. It is further to be observed 

 that Fusus decemcostatus replaces the closely sWied F. tor natus. 

 that Saxicava rugosa is much less abundant, that modern 

 Astartes appear instead of A. Laurentiana, and that Mytitus 

 edulis isof large size and of the ordinary form. These differences 

 are however probably nothing more than the effects of the more 

 oceanic position of the Portland beds, as compared with the 

 old inland sea of the St. Lawrence valley, and it will be observed 

 that in respect to the Astartes the Portland beds correspond 

 with those of Labrador. The less elevation of the Portland beds 

 however renders it probable that they are somewhat newer than 

 those of the St. Lawrence valley and of Lake Champlain. 



In the cabinet of Dr. Jackson of Boston, I had an opportunity 

 of examining a collection of about 14 species obtained by him 

 from the beds on the Pressumpset River, described many years 

 ago by Professor Hitchcock and Dr. Jackson. In this collection 

 while several of the shells found at Portland are absent, I found Leda 

 Portlandica, ^ Nucula proxima, Terehratula septentrionalis^ 

 My a arenaria, and the carapace of a crab. 



3. OCCURRENCE OF FRESH WATER SHELLS IN THE PLEIS- 

 TOCENE BEDS. 



I owe to the kindness of A. Dickson, Esq., additional collections 

 of the fresh water shells and the sands containing them from Paken- 

 ham,f together with a communication from a gentlemen of that 

 place giving a section of the deposits as seen in a deep road 

 cutting. The arrangement is as follows in descending order : 



Sand and surface soil, about, 10 feet 



Clay, 10 « 



* Dr. Gould informs me that he is now satisfied of the correctness of 

 the identification of this shell by Mr. Wood with the species L. truncata 

 of the British Pleistocene and of the artic seas, where it has been found 

 living. 



t See my paper, Canadian Naturalist, Vol. IV. 



