GEOLOGY, 



ON CLAYS CONTAINING OPHIOLEPIS GEACILIS AND 

 . OTHEK ORGANIC EEMAINS, WITH NOTES ON EECENT 

 GEOLOGICAL EOEMATIONS NEAE ST. ANDEEWS. 



BY ROBERT WALKER, F.G.S.E. 



ON the East Coast of Scotland the Glacial deposits are 

 fairly represented in the Boulder and Brick Clay series. 

 The latter is distributed here and there along the lowlands, 

 in the main at no great distance from the sea, but it is some- 

 times met with at a considerable height above it. 



Although these clay beds have been worked for years at several 



places, as yet comparatively few organic remains appear to have 



been found in them. Taken in all, the record they have furnished 



of the animal and plant life of the land and sea at the period 



of their deposition, is on the whole arathermeagre one; as far as it 



goes, however, it is of considerable scientific importance. No 



doubt this is made more prominent than it would otherwise be 



from the comparison we are apt to institute between the 



scant remains yielded by these deposits, and the rich fossili- 



ferous contents of the clays on the west coast of Scotland. 



Thus, if we take the shells as one of the leading features of 



these formations, we find that the west coast beds have afforded 



about 234 species, while those on the east coast have produced 



about sixty species. This is exclusive of the Caithness shells, 



which are stated to be from boulder clay. The same thing is 



observable in the case of the other invertebrate animals : they are 



all more numerous in the west coast deposits, than in those of 



the east. 



There may be various reasons brought forward to ac- 

 count for this discrepancy. The main cause appears to me 

 to be that the brick clay, of the east of Fife at any rate, is an 

 older member of the Glacial series, than the shell-bearing 

 clay of the west coast, and I consider that it occupies the same 



