328 Reports and Proceedings. 



Geological Society of London. 



April 15tli, 1874.— John Evans, Esq., F.E.S., President, in tlie 

 Chair. The following communications were read : — 



1. "About Polar Glaciation." By J. E. Campbell, Esq., F.G.S. 



The author commenced by referring to a reported statement of 

 Prof. Agassiz, to the effect that he supposed the northern hemisphere 

 to have been covered in glacial times from the pole to the equator 

 by a solid cap of ice. He described his observations made during 

 33 years, and especially those of last summer, when he travelled 

 from England past the North Cape to Archangel, and thence by 

 land to the Caucasus, Crimea, Greece, and the South of Europe. 

 His principal results were as follows : — In advancing southwards 

 through Eussia a range of low drift hills occurs about 60° N. lat., 

 which may perhaps form part of a circular terminal moraine left 

 by a retreating polar ice-cap ; large grooved and polished stones of 

 northern origin reach 55° N. lat. at Nijni Novgorod, but further east 

 and south no such stones could be seen. The highest drift beds along 

 the whole course of the Volga seem to have been arranged by water 

 moving southwards. In America northern boulders are lost about 

 89°, in Germany about 55°, and in Eastern Eussia about 56° N. lat., 

 where the trains end and fine gravel and sand cover the solid rocks. 

 Ice-action, in the form either of glaciers or of icebergs, is necessary 

 to account for the transport of large stones over the plains, and the 

 action of moving water to account for drift carried further south. 

 There are no indications of a continuous solid ice-cap flowing south- 

 ward over plains in Europe and America to, or nearly to, the 

 Equator ; but a great deal was to be found on shore to prove ancient 

 ocean circulation of equatorial and polar currents, like those which 

 now move in the Atlantic, and much to prove the former existence 

 of very large local ice-systems in places where no glaciers now exist. 



Discussion. — Mr. Belt stated that he had been over much of the same ground as 

 the author, but had come to quite opposite conclusions. He agreed with Mr. Camp- 

 bell that boulders only come down to a certain point, but he considered that the 

 Ycry plains themselves are proofs of glacial action. He thought that the absence of 

 boulders is only a proof that there was no chain behind which could supply the 

 requisite rock, and in this case the only signs of the existence of a Polar ice-cap 

 would be due to the blocking up of the drainage by it, resulting in the formation of 

 the plains of Siberia. 



Prof. Eamsay thought that the ideas put forward by the author were in accordance 

 with those of previous writers, hut he considered that he exaggerated the power of 

 ice in the shape of icebergs to effect changes. The question was whether there were 

 ice- caps moving towards the equator, or whether the configuration of the mountain 

 regions might have produced the observed effects. He expressed himself satisfied 

 that the present configuration would account, at least to a great extent, for the 

 changes which have taken place. The boulders found on the great plain of Russia 

 might have been conveyed either directly by glaciers, or by icebergs broken oS the 

 ice-cap itself. Boulders have been seen 40 miles north of the Caucasus, proving the 

 existence there of great ancient glaciers. The absence of boulders on the plains of 

 Siberia was, he thought, to be accounted for by the absence to the north of Siberia 

 of high land from which such boulders could be carried. 



Mr. Drew thought that sufficient consideration had not been given to the relative 

 levels of the old and new glaciers. In Cashmere he had observed a difference of 

 5000-6000 feet. 



