SOUTH LANCASKEKE, CHESHTEE, A:N^D THE WELSH BOEDER. 373 



made hj Mr. James Eccles on the outcrops of some Carboniferous 

 strata near Blackburn *. In this case also the dragging over of the 

 edges of the beds was to the S.S.E. 



While, however, this doubt exists in the case of the striae, the 

 fact of the materials of which the drift of South Lancashire and 

 Cheshire is composed having travelled in a S.S.E. direction is capable 

 of easy proof. The greater number of the boulders have been 

 derived from the Lake District, and are imbedded with fragments 

 of, and in a matrix derived from, the Carboniferous and Triassic 

 rocks of Lancashire ; they are accompanied, in smaller quantities, 

 by Scotch granitic rocks, and by flints and hardened chalk from the 

 north of Ireland f. Southwards, i. e. on receding from the source 

 of supply, the boulders become fewer in number and the clay 

 more homogeneous. At the same time, on passing southwards 

 from the Lancashire Coal-field on to the Triassic area of Cheshire, 

 the red tinge of the Boulder-clay becomes steadily stronger. So 

 gradual, however, are these changes that it is only by comparing 

 distantl ocalities that they can be fully realized. 



The sands and gravels provide further evidence of the existence 

 of currents flowing from the N.lSr.W. These deposits, which usually 

 underlie Boulder- clay, in certain areas rise to the surface in mounds or 

 long banks, throwing off the Boulder-clay on either side, and running 

 for two or three miles across the plain J. While from their form, and 

 in their composition of stratified beds of sand and shingle with shell- 

 fragments, these banks are clearly the result of marine currents, 

 from their direction, and by the fact of their frequently starting 

 from the south-east side of a hilL, they show that those currents flowed 

 from the J^.IST.W. jSTor is there any evidence in the drifts of South 

 Lancashire and Cheshire of there ever having been much variation 

 from this direction ; for the percentage of boulders and the com- 

 position of the drifts are very similar from top to bottom, nor is it 

 possible to detect any such marked differences between the upper 

 and lower beds as to make the application of such names as the 

 Upper or the Lower Boulder-clay possible. Thus the direction in 

 which the drift has been transported agrees with that in which the 

 edges of the outcropping beds have been forced, and with the 

 prevalent direction of the glacial striae. The two former having 

 been exclusively in a south-south-easterly direction, it seems extremely 

 probable that the striating agent moved in this direction also. 



Lastly, it is almost invariably under Boulder-clay that the rock 

 has been found to be striated. Though the sands and gravels are 

 included among the glacial deposits, the Boulder-clays alone show 

 direct evidence of the action of ice. In them alone are found 

 scratched stones, even in the smaller masses included or interbedded 

 in the sand ; and though sometimes rudely stratified, they are usually 



* Trans. Geol. Soc. Manchester, vol. rii. p. 20. 



t Mackintosh, " Eesults of a ... . Survey .... of the Erratic Blocks .... of 

 the West of England and East of Wales," Quart. Journ. Geol. Soc. vol. xxxv. 

 p. 425 (1879). 



I " Geology of Chester " (Geol. Survey Memoir), p. 16 (1882). 



