8. V. Woodjj'un. — American and British Surface-Geology. 17 



Part of the beds of the St. Lawrence basin above tabulated with 

 the English beds posterior to the general emergence, have already- 

 been tabulated beside the English Middle and Upper Glacial ; but 

 having given my reasons for thinking it probable that they may not 

 be synchronous with these, but be posterior to the major glaciation, 

 I have now placed them in the position of synchronism to which 

 the probabilities seem to point. 



In the American portion of the deposits thus tabulated, the first, 

 or forest beds, seem to me, if in situ, to have been formed during that 

 temperate period which, following the elevation of England from the 

 chief part of its general submergence, was accompanied there by 

 the reintroduction of the great mammalia, and succeeded by the 

 minor glaciation. The beds 3a appear to me to mark the culmi- 

 nation of this minor glaciation when the dissolution of the glacier 

 which rested on the Canadian Highlands filled the lake- basin with 

 freshwater, over which berg and other ice floated. The marine 

 clays of the Lower St. Lawrence and Atlantic coast seem to me to 

 belong to the same period, when in Lower Canada the glacier-ice 

 terminated in the sea-water of the Gulf of St. Lawrence, and to 

 have accumulated in the sea which followed the recession of the ice 

 until the area they occupy was raised above its level. 



The Eskers and Kames of the Canadian Highlands seem to me to 

 mark the wane of this minor glaciation, and to represent the moraine 

 of the ice after it had ceased to reach the sea or lake-waters ; while 

 the successive terraces formed by the beds No. 4 indicate the suc- 

 cessive falls in the water of the lake-basin, as the ice of this minor 

 glaciation wasted out of the narrow throat of the St. Lawrence 

 valley, and so allowed the waters to escape from the lake-basin into 

 the Gulf of St. Lawrence. 



As already observed, the Mississippi Bluff formation appears to 

 have been in progress throughout both the Glacial and post-Glacial 

 periods, that is, throughout the major and minor glaciations. 



In the English part of the deposits last tabulated, thei'e has long 

 seemed to me to have been one return of cold after the country had 

 emerged from the depression at the end of which the Moel Tryfaen 

 sands were formed, and had become stocked with the great mammalia. 



In describing the beds of South-east Yorkshire and Lincolnshire, 

 in the year 1867,' Mr. Eome and I distinguished those which ap- 

 peared to us of Glacial age from certain others which, overlying 

 these, were unconformable to and overlapped them in the direction 

 of the Chalk Wold. These overlying and overlapping beds we 

 called the " Hessle," and referred to the post-Glacial period, i.e. to a 

 time posterior to the general emergence of the country from its 

 great depression and glaciation. These beds, consisting of a fos- 

 siliferous sand and gravel confined to low elevations, and of a clay 

 with boulders (mostly very small, but occasionally of larger dimen- 

 sions), and other debris overlying it, and reaching to higher 

 elevations than the gravel, we subsequently to the publication 

 of our paper traced to the borders of Durham ; and, in the case of 

 1 Quart. Journ. Geol. Soc. vol. xxiv. p. 146. 



DECADE II. VOL. V. — NO. I. 2 



