Remeivs — Br. Damson's Canadian Geology. 41 



Although Dr. Dawson states that the coup de grace has been given 

 to the American continental glacier theory,— and that too by excess 

 of zeal in its advocacy on the part of Prof Dana ! — yet we cannot 

 think that old sea-beaches can ever, in a majority of cases at least, 

 be mistaken for moraine-heaps by any tolerably keen-eyed field- 

 geologist. 



The great value of Principal Dawson's paper is however by no 

 means lessened by its strongly controversial character ; and the large 

 amount of clearly recorded facts which it contains must earn for 

 it a high position as a work of reference concerning the regions of 

 which it more especially treats. 



The palseontological part of the Memoir is very full, but is not 

 drawn up so as to be easily consulted for stratigraphical purposes. 

 About 205 species are enumerated, all of which, with the exception 

 of three or four, are recent northern or arctic forms. Of these 16 

 only appear to belong to the Saxicava sand, including five land and 

 fresh- water shells, which "seem to have been drifted by some fresh- 

 water stream into the sea of the Saxicava sand and Leda clay." 

 Four of the marine specie^ have not been found below the Saxicava 

 sand, but the rest are common to it and to the Leda clay. The 

 great mass of the fossils is found immediately below the Saxicava 

 sand in the upper layers of the Leda clay, the main portions of both 

 deposits being comparatively barren. A new shell from the Leda 

 clay is described in the paper before us under the name of Choristes 

 elegans; this is indeed the only new species found apparently in 

 these beds. Among the Foraminifera we notice the occurrence of a 

 representative of the genus Saccammina, a genus first dredged up 

 by Sars, who named it, which was next found fossil in a bed of 

 Limestone of Lower Carboniferous age in Northumberland, and de- 

 scribed (S. Carteri) by Mr. H. B. Brady, and which it is interesting 

 to find turning up again unexpectedly (apparently in a stunted form) 

 in glacial beds on the other side of the Atlantic. 



The fauna of the Boulder-clay, on which Dr. Dawson must 

 necessarily rely to a great extent in pronouncing it to be of marine 

 origin, is very restricted, consisting (so far as we can make out from 

 a study of the lists given) of only seven species, all except one 

 common to both Boulder and Leda clay. The localities in which the 

 Boulder-clay is fossiliferous are all, it seems, situated near and about 

 the mouth of the St. Lawrence, being quite barren of fossils further 

 up. This appears to us to be a point of some importance scarcely 

 dwelt upon sufficiently by our author. 



In conclusion, we cannot do better than let Dr. Dawson give, in 

 his own words, a summary of his views on the character and 

 sequence of the phenomena connected with the glaciation of Canada : 



" In the earlier part of the (Glacial) period, the elevated land of 

 the Pliocene epoch gradually sank under the waters, and the remainder 

 of it became refrigerated and covered with snow and ice. At the 

 period of greatest subsidence, nearly all the hills were submerged, 

 and heavy ice from the north ground over their summits ; while the 

 upper part of the Boulder-clay and the lower beds of the Leda clay 



