40 ADDRESS TO THE BRITISH ASSOCIATION, 1881. 



and rain charts, and last, but not least, by his work on 

 the physical geography of the sea, gave the first great 

 impulse to all subsequent researches.' 



But the progress in our knowledge of geography is, 

 and has been, by no means confined to the improve- 

 ment of our maps, or to the discovery and description 

 of new regions of the earth ; it has extended to the 

 causes which have led to the present configuration of 

 the surface. To a great extent indeed this part of the 

 subject falls rather within the scope of geology, but I 

 may here refer, in illustration, to the distribution of 

 lakes, the phenomena of glaciers, the formation of 

 volcanic mountains, and the structure and distribution 

 of coral islands. 



The origin and distribution of lakes is one of the 

 most interesting problems in physical geography. That 

 they are not scattered at random, a glance at the map 

 is sufficient to show. They abound in mountain dis- 

 tricts, are comparatively rare in equatorial regions, 

 increasing in number as we go north, so that in Scot- 

 land and the northern parts of America they are sown 

 broadcast. 



Perhaps a priori the first explanation of the origin 

 of lakes which would suggest itself, would be that they 

 were formed in hollows resulting from a disturbance of 

 the strata, which had thrown them into a basin-shaped 

 form. Lake-basins, however, of this character are, as a 

 matter of fact, very rare ; as a general rule lakes have 

 not the form of basin- shaped synclinal hollows, but, 

 on the contrary, the strike of the strata often runs 

 right across them. My eminent predecessor, Professor 

 Ramsay, divides lakes into three classes : (1) Those 



