April 3, 1876.] , ^51 [Price. 



greater than we witness. By the impulse that produced the rotation of 

 the Earth on its axis, the sliape of the globe was reduced from a sphere 

 to an oblate spheroid, by the flattening of the Poles, ^nd that cause forbade 

 mountains rising at the Poles. It is necessary that we keep the above 

 principles and facts in view as we proceed. The height of mountains, and 

 seas open to the Poles are both causes of glaciation, and not to be over- 

 looked, but cannot be cause of the continental ice-sheet. 



Having stated the theory of the great glacial ice-sheet, and the facts 

 upon which the glacialists place it, it seems expedient, considering how 

 generally it has been accepted, to take yet closer and broader views of 

 other facts and laws requisite to correct conclusions, many of them fur- 

 nished by the glacialists themselves, but looked at by other eyes, these 

 may aflbrd proofs that should conduct to an opposite induction. 



The u nut ratified drift, or boulder clay, or Till, is a chief argument for 

 the continental Arctic sheet of ice. Grant it came from beneath ice, that 

 fact does not prove that it came from a polar ice-sheet, for it might be from 

 glaciers of contiguous mountains, or ices floating down from the North. 

 Dr. Dawson say : "It may be viewed as consisting of a base or paste in- 

 cluding angular and rounded fragments of rocks. The base varies from a 

 stiff clay to loose sand, and its composition and color generally depend 

 upon those of the underlying and neighboring rocks. Thus, over sand- 

 stones it is arenaceous, over shales argilaceous, and over conglomerates and 

 hard slates, pebbly or sliinglj'. The greater number of the stones con- 

 tained in the drift are usually like the paste containing them, derived from 

 the neighboring rock formations." Acadian Geology, 59. In Brazil it is 

 "ochraceous, highly ferruginous, sandy clay." Agassiz, 399. This is evi- 

 dence that the source of the Till is local and co-extensive with a local cause 

 and source ; but as the Andes are of immense height and running the 

 length of South America and covered by perpetual glaciers, so the 

 manufacture of the paste is present through all time ; and the frosts and 

 rains have ever since the Cordilleras were raised, spread it over the declin- 

 ing surface towards and to the Atlantic. With this etei'ual winter ever 

 present upon the Andes, even under the Equator, it does not seem neces- 

 sary that we should seek a cause in a gi'eat "cosmic winter," "of univer- 

 sal cold," which may have lasted "for thousands of centuries," for so 

 much Agassiz says. We need not then go to a polar ice-cap for an ex- 

 planation. The Till may be there from normal causes, and thus be yet 

 spreading over the surface. 



Agassiz rejects the idea of deposition under the sea, because there are no 

 marine remains in the strata of rocks or their covering. He says : "It is 

 my belief that all these deposits belong to the Ice Period in its earlier or 

 later phases, and to this cosmic winter, which, judging from all the phe- 

 nomena connected with it, may have lasted for thousands of centuries, we 

 must look for the key to the geological history of the Amazonian Valley. 

 I am aware that this suggestion will appear extravagant, but is it, after all, 

 80 improbable, when Central Europe was covered with ice thousands of 



