On the ''HasslerT 



159 



trend of the glacial abrasions must be from the 

 south northward, the lee-side of abraded rocks must 

 be on the north side of the hills and mountain 

 ranges, and the bowlders must have travelled from 

 the south to their present position. Whether this 

 be so or not, has not been ascertained by direct 

 observation. I expect to find it so throughout the 

 temperate and cold zones of the southern hemi- 

 sphere, with the exception of the present glaciers of 

 Terra del Fuego and Patagonia, which may have 

 transported bowlders in every direction. Even in 

 Europe, geologists have not yet sufficiently discrimi- 

 nated between local glaciers and the phenomena 

 connected with their different degrees of successive 

 retreat on the one hand ; and, on the other, the facts 

 indicating the action of an extensive sheet of ice 

 moving over the whole continent from north to 

 south. Among the facts already known from the 

 southern hemisphere are the so-called rivers of stone 

 in the Falkland Islands, which attracted the atten- 

 tion of Darwin during his cruise with Captain 

 Fitzroy, and which have remained an enigma to this 

 day. I believe it will not be difficult to explain 

 their origin in the light of the glacial theory, and 

 I fancy they may turn out to be ground moraines 

 similar to the 'horsebacks' in Maine. 



You may ask what this question of drift has 

 to do with deep-sea dredging ? The connection is 

 closer than may at first appear. If drift is not of 

 glacial origin but is the product of marine currents, 

 its formation at once becomes a matter for the Coast 

 Survey to investigate. But I believe it will be 



