126 



MR. H. KTNASTON ON THE 



[May 1894, 



graben, scarcely anything can be seen of the actual beds in situ, the 

 steep sides of the ravine consisting of disintegrated shale and marl 

 in an almost soil-like condition, throughout which the various 

 characteristic fossils are loosely scattered, though generally merely 

 as casts or in a more or less fragmentary condition. This is usually 

 the case when the slope of the sides of the ravine is gentle enough 

 to allow of the disintegrated material of the rock resting upon them, 



Tjpo. Etching Co.Sc. 



and with this are mingled soil and plant^remains from above, 

 boulders, pebbles, and innumerable shells of land-molluscs. Great 

 masses of soil and rock may sometimes slip down from the upper 

 part of the banks, bringing with them trees and shrubs, and in this 

 way a portion of the ravine may in process of time become inextri- 

 cably choked up by a confused mass of the trunks and branches of 

 dead fir-trees, masses of soil, boulders, and disintegrated marl, the. 



