236 WARREN . UPHAM^ ESQ.^ ON CAUSES OP THE ICE AGE. 



already indicated may sutEce to sliow that the hypothesis is not onlv 

 baseless, but wholly fails to explain the facts, most of which in fact tell 

 strongly against it. It accounts neither for the wide-spread phenomena 

 of the Ice Age, nor for the remarkable climatic conditions of interglacial 

 times. 



Somewhat similar objections are apparent to me. 



An important question for geologists to decide is Avbether one, 

 two, or more second rotations occurred under snch conditions as 

 now prevail, viz., witli a radius at, or near to, 29° 25' 47", or 

 whether only one such second rotation took place, with no inter- 

 glacial conditions. For my own part, I place more dependence on 

 a geometrical proof, corroborated by recorded observations, and 

 which states the dates when certain phenomena vmst have occurred 

 long before these dates were suspected to be even approximate, 

 than I do on any hypothesis framed to explain effects, when it ha& 

 been found that these effects occurred at certain dates. 



THE AUTHOR'S REPLY. 



Respecting the greater part of the criticisms and questions 

 brought forward in these discussions, no detailed reply seems to 

 be needed. In part the different comments and communications 

 sufficiently answer one another ; and in other instances a careful 

 reading of the paper will make my views more clear and perhaps 

 more acceptable. 



To Mr. Gooch it may be answered, in addition to the remarks 

 of Professor Lobley, that the transmission of the earth's internal 

 heat through the cooled crust appears to me certainly to have been 

 so slow and of such small amount as to be quite unimportant in its 

 influence on the mean temperature of the atmosphere during the 

 late eras of geologic time mentioned, which far antedate the Ice 

 age. 



Professor Geikie's objections to my explanation of the causes of 

 accumulation of continental ice-sheets were elaborately presented 

 in his valuable paper in the twenty-sixth volume of this journal : 

 and in the ensuing pages 254-256 of that volume, my answers 

 to his arguments are stated, but less fully than here. It is 

 my belief that the long continued pre-glacial uplift of the far 



