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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 26, 



mington can be traced under the Till, which we know to be abundant 

 in that vicinity, it would offer phsenomena analogous to the marine 

 bed of which there are traces at Runton, in Norfolk, above the 

 freshwater beds*, indicating the existence of ordinary marine con- 

 ditions at the commencement of the submergence, before the setting 

 in of the peculiar agencies which produced the Tillf. 



The accompanying diagram, fig. 1, represents the successive ter- 

 races of reconstructed erratic materials, on the banks of the river at 

 Congleton, and the cliff of red marl and erratic tertiaries on the right 

 bank. Fig. 2 represents the succession of erratic deposits from the 

 cliff at Congleton to Alderley Edge. 



Fig. 1. — Section across the Valley of the Bane from Congleton to 



Buglawton. 



Horizontal scale 1 mile to 2 inches. Vertical scale 240 feet to 1 inch. 

 N.E. s.w. 



b. Lower Erratics. Till. d, e, f,f. Reconstructed gravel. 



c. Thin bed of sand, sometimes gravelly. 



North of Alderley Edge to Stockport, the surface is chiefly clay, 

 varied by outliers of the Upper Sands, and by accumulations of re- 

 constructed erratic materials, which border the line of the Boiling, at 

 various levels. At Stockport the Mersey has cut a channel, twenty 

 feet deep, in sandstone of the New Red. The higher parts of Stock- 

 port appear to stand on sand, resting on clay which has sand between 

 it and the rock. In the lower ground, along the line of the railway 

 to Manchester, the surface is chiefly a clayey loam, which, in the 

 brickfields at Manchester, passes down into a very tenacious Till, 

 with much fragmentary limestone. On the higher grounds about 

 Manchester, as at Cheetham Hill, are outliers of sand resting on Till. 



In no part of the lines of railway from Alderley to Manchester, 

 and from Congleton to Stockport, are there cuttings which now ex- 

 hibit the stratification to a greater depth than thirty feet ; and in 

 none have I observed the rock. From a combination of all the sec- 

 tions observed with the estimated height of the hills of erratic deposits 

 which rise above them, I cannot estimate the depth of these deposits 

 at less than 150 feet, of which about 50 may consist of Till. 



Scratched Detritus of the Till. 



In the Upper Erratics of the different districts which I have at 

 various times examined, I have seen deep scorings on some of the 

 large blocks, particularly the local blocks ; but I believe that the 



* Quart. Journ. Geol. Soc. vol. vii. p. 20. par. 2. 



f See also Quart. Journ. Geol. Soc. vol. vi. p. 386, for notices by Mr. Smith of 

 Jordan Hill of exceptional cases of sand with shells below the Till. 



