THE 



POPULAR SCIENCE 

 MONTHLY. 



APRIL, 1874. 



THE AGE OF ICE. 1 



TILL within a comparatively recent time, geologists regarded 

 the climate of the prehistoric periods as tropical or warm tem- 

 perate. Those who first sought to explain the presence of certain 

 scratches upon ledges, by the action of moving ice in continental 

 masses scouring the surface, were met by ridicule and skepticism. The 

 writer has now before him a caricature devised to illustrate the no- 

 tions of the literary world upon this subject thirty years since in Eng- 

 land. The excellent Dr. Buckland appears clad in furs, such as are 

 required in Greenland, with a map of ancient glaciers under his arm, 

 showing markings made on the rocks 33,333 years ago. On one side 

 is represented a bridge with a scratched paving-stone at the entrance, 

 and an inscription like this : " Scratches made day before yesterday 

 by a cart-wheel passing over Waterloo Bridge." It is said that the 

 learned doctor was greatly amused by the sketch, and sent copies of 

 it to all his scientific friends. The one before us bears his autograph. 



But within the last three decades numerous observers have carried 

 out the suggestions of the earlier geologists to a very extensive appli- 

 cation. Forbes and Agassiz explored the glaciers of Switzerland in 

 order to learn the laws of ice-motion ; Lyell, Murchison, Ramsay, and 

 others, have ransacked the fields of Great Britain in search of facts 

 from which to generalize ; and, in our country, Hitchcock, Mather, 

 Whittlesey, Newberry, Dana, and a score of younger men, have made 

 the investigation of the drift period a matter of enthusiasm. The ex- 

 istence of an immense era when all of Northern America and Europe 

 was enveloped by enormous thicknesses of solid ice, crunching frag- 

 ments of rocks beneath its massive tread, and transporting square 

 miles of moraine rubbish upon its back, is now universally accepted. 

 Some have gone so far as to believe that the entire globe was encircled 



1 The Great Ice Age, and its Relation to the Antiquity of Man. By James Geikie, 

 F. R. S. E., F. G. S. 575 pages. D. Appleton & Co. 

 vol. iv. — 41 



