Vice-President's Address. 195 



climatic conditions. When our winter happened in aphelion 

 new snow-fields miglit have appeared, or already existing 

 glaciers might have increased in size ; while, with the winter 

 in perihelion, the temperature of northern latitudes would 

 doubtless be raised. But the general result would simply be 

 an alternation of warm and somewhat cooler conditions. 

 And such fluctuations of climate might readily have taken 

 place without materially modifying the life of the period. 



The breccias of the Permian system have been described 

 by Kamsay as of glacial origin. Some geologists agree with 

 him, while others do not — and many have been the ingenious 

 suggestions which these last have advanced in explanation 

 of the phenomena. Some have tried to show how the stones 

 and blocks in the breccias may have been striated without 

 having recourse to the agency of glacier ice, but they cannot 

 explain away the fact that many of the stones (which vary 

 in size from a few inches to three or four feet in diameter) 

 have travelled distances of thirty or forty miles from the 

 l)arent rocks. Similar erratic accumulations, which may 

 belong to the same system or to the Carboniferous, occur in 

 India and Australia. According to Dr Blanford, the Indian 

 boulder-beds are clearly indicative of ice-action, and he does 

 not think that they can be explained by an assumed former 

 elevation of the Himalaya. On the contrary he is of opinion 

 that the facts are best accounted for by a general lowerinfT 

 of the temperature, due probably to the action of cosmical 

 causes. Daintree, Wilkinson, E. Oldham, and others who 

 have studied the Australian erratic beds, have likewise stated 

 their belief that these are of true cjlacial orisin. 



I may pass rapidly over the Mesozoic systems, taking 

 note, however, of the fact that in them we encounter 

 evidence of ice-action of much the same kind as that met 

 with in Palaeozoic strata. While, on the one hand, the 

 Mesozoic floras and faunas bespeak climatic conditions 

 similar to those of earlier ages, but probably not quite so 

 uniform; on the other, the occurrence of erratics in various 

 marine accumulations is sufficient to show that now and 

 again ice floated across seas, the floors of which were 

 tenanted by reef-building corals. The geogr.iphical con- 



