392 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 8, 



Note on the Shells from the Lower Bouldee-clat of Dawpool. 

 By Searles V. Wood, juu., Esq., P.G.S, 



The shells are far less fossilized than those from our East-An- 

 glian glacial beds and those from the Bridlington bed, and are all 

 common shells of the British littoral region *. The Lower Boulder- 

 clay from which they come I regard as belonging to the latest part 

 of the Glacial sequence — later, that is, than the newest of our East- 

 Anglian beds. The upper clay of Dawpool cliff (which is the same 

 as the apparently uniform deposit of Upper Boulder-clay which 

 extends through the lower grounds of North Wales, Cheshire, and 

 Lancashire) seems to me not improbably the same as the Hessle clay 

 of Yorkshire, which is obviously a deposit due to a postglacial 

 (partial) resubmergence subsequently to the general emergence of 

 the country from the glacial sea, and its reoccupation by the great 

 mammalia. 



DiSCXJSSIOK. 



Prof. Ramsat remarked, with regard to the Bridlington beds 

 which had been cited, that they were probably preglacial, and not 

 glacial. He thought that eventually it would be proved that during 

 the Glacial Period there had been several oscillations in this country 

 both in level and in temperature. With respect to temperature, 

 the calculations of Mr. Croll showed the extreme probability of 

 such variations being due to astronomical causes : and these were 

 best illustrated by reproducing his figures in the form of a diagram 

 showing the curves and oscillations of temperature. 



4. On Modern Glacial Action in Canada. 

 By the Rev. William Bleasdell, M.A. 



(Communicated by Principal Dawson, T.E.S., F.G.S.) 



Second Article. 



Further inquiry into the action of ice in Canada furnishes new 

 facts illustrating the powerful effects of this agent in changing or 

 modifying the Boulder-drift surfaces of the country lying over the 

 Silurian strata, even during the period of human observation ; and 

 if so, how much more of change must have been effected in this 

 way during that comparatively long period which, as far as Canada 

 is concerned, may be designated prehistoric, when it lacked ob- 

 servers to note, and a written language to record, those changes 

 which must have occurred in the bygone centuries of its existence 

 in its present form, and subject to the same powerful glacial agen- 

 cies and climate ? In addition to the facts furnished to the Geological 

 Society, and kindly received by it, in my previous paper t, I am now 

 in a position to lay before the Society further evidence of this nature. 

 At the head of that arm of Lake Ontario named the Bay of 



* [The species of shells I sent to Mr. S. V. Wood, jun., did not include all 

 those above named by Mr. Gwyn Jeffreys. — D. M.] 

 t See Quart. Journ. Geol. Soc. vol. xsvi. p. 669. 



