Rogers.] 242 



All geologists who have studied the phenomena of the later Ter- 

 tiary Ages, admit that there was an abnormally cold or very snowy 

 era, in certain parts of our earth's surface, about the end of the 

 Pleistocene Period. 



The indications from organic remains, and the physical move- 

 ments and impressions, all concur to prove that this refrigeration of 

 the surface, late in the " Great Tertiary Day," was local and not 

 world-wide. 



No satisfactory evidence has yet been adduced to show that this 

 chilling of our world's climate was cosmic al or general, while all the 

 testimony I have been able to examine, convinces me that it was 

 essentially geographical, and intimately connected with, or dependent 

 on, special conditions in the distribution of the waters and the clay- 

 lands of the period. 



Astronomy, in fact, all physical science, refuses to explain, or indeed 

 to accept the notion of a general terrestrial, somewhat abrupt, cool- 

 ing and subsequent heaving up. They fail to suggest any competent 

 cause as much as geology refuses to produce any acceptable proofs. 

 I wish to abstain, in toto, at present, fifom all discussion of this ques- 

 tion, partly because I conceive that it befits more a Society of Physi- 

 cists than one of Naturalists. 



The phenomena T wish to account for are local upon our earth, 

 though of wide geographic distribution, and I hold it to be far more 

 philosophic to seek for their solution in geographical facts and laws, 

 than in hypotheses, which invoke an appeal to agencies in nature, 

 far beyond and without the pale of the appearances to be explained. 

 I prefer to try to elucidate geographical phases in geology by refer- 

 ence to geographical causation. 



Waiving the much mooted topics of Diluvial and Glacial action, I 

 propose to restrict myself to a description of certain admitted geolog- 

 ical facts connected with the most superficial deposits of Great 

 Britain, indicative of a cold or icy period ; and to a statement of 

 other facts recently collected by me, which I think plainly indicate 

 how that cold state of the surface was produced. 



• During the last few years evidence has been rapidly accumulating 

 in England and Scotland, especially in the latter country, through the 

 researches of zealous naturalists, that the organic remains of the 

 most superficial deposits, more particularly those of the "Brick Clays" 

 and their associated " Sandy Silts," which skirt both the eastern and 

 western margins of the Island, like a narrow selvage, and occupy the 

 beds and borders of its many bays and broad inlets, always at or only 

 very little above the existing sea-land, are all of them of a more or 

 less cold or Arctic type. Mr. Smith of Jondon Hill, and Rev. Henry 

 W. Croskey, both of them diligent and successful collectors, have 



