OH. IV] PRESERVATION OF PLANTS 61 



the mountain sides like the 'columns of a ruined 

 temple.' The height of the river at the foot of the 

 chff is 6/00 ft. above sea-level and the mountain 

 rises to a height of 9400 ft. above the sea. In the 

 lower part of the section the volcanic strata are seen 

 to rest on a foundation of older rocks A, and these 

 in turn were laid down on the eroded surface of a 

 still more ancient foundation, J5(36). 



The section as a whole affords a striking demon- 

 stration of the magnitude of earth-movements since 

 the last of these forests was buried below the 

 surface of a sea in which the volcanic material was 

 deposited. The account of the Yellowstone Park 

 section recalls Darwin's description in the Natural- 

 ises Vo I/age (.S7) of snow-white columns projecting 

 from a bare slope, at an altitude of 7000 ft. in the 

 Cordillera. 



The abundance of drift wood on the coasts of 

 some countries at the present day helps us to picture 

 the conditions under which the remains of former 

 forests have been preserved. In his Letters from 

 High Latitudes, Lord Dufferin gives the following 

 description of drift-wood on the shores of Spitz- 

 bergen : — ' A little to the northward, I observed, 

 lying on the sea-shore innumerable logs of drift-wood. 

 This wood is floated all the way from America by the 

 Gulf Stream, and as I walked from one huge bole 

 to another, I could not help wondering in what 



