IG 



them are grooved and scratched, but with much irregularity. 

 The grooved specimens do not generally look like rocks that 

 had been grooved by the glaciers of an alpine valley ; but 

 rather like rocks which, having been mechanically acted on by 

 the drifting ice of a glacial shore, had then been borne away on 

 ice-rafts, and stranded on the hills where we now find them. No 

 shells, or other organic remains, have been found in these 

 deposits of coarse Gravel." 



I have quoted the above passage in full, in consequence of 

 the accurate observations and acute deductions it contains, 

 which partially anticipate the conclusions arrived at in a sub- 

 sequent part of this essay. Prof. Sedgwick proceeds to notice 

 the flint-gravel covering the plains bordering on the Cam, and 

 he still refers the formation of these gravels to the "long con- 

 tinued action of the waters of the sea, as it was gradually 

 falling to its present level, near the end of the glacial period," 

 although he observes that the stones are more angular and less 

 waterworn than in most marine gravels. As reg^ards the rela- 

 tive ages of these deposits, he knew of no evidence to show 

 whether the Boulder Clay is older or younger than the coarse 

 Gravel. But he mentions the fact of flint Gravel overlying the 

 Boulder Clay near Ely, and also on the St Neots road, a few 

 miles from Cambridge. 



Lastly, the marine Gravels at March are referred to, and the 

 indications of their dipping under the Boulder Clay are spoken 

 of as doubtful. The large clay-pit near Ely, called Roslyn or 

 Rosswell Hole, is referred to at p. 28 of Prof. Sedgwick's paper 

 just mentioned, and a diagrammatic section is given of the beds 

 therein exposed. 



1864 — 5. This pit is the subject of subsequent papers by 

 Mr Seeley, entitled " On a Section of the Lower Chalk at Ely," 

 Geol. Mag. i. p. 150, and "On a section discovering the Creta- 

 ceous beds at Ely," Geol. Mag. ii. p. 529. In the former 

 Mr Seeley gives a description of the appearance which the beds 

 presented before the year 1862, and adopts the explanation of 

 their relative position which had previously been suggested by 

 Prof. Sedgwick, viz. that Chalk and Boulder Clay had been 

 faulted down together against the Kimmeridge Clay. In the 

 latter he cjives a sketch of the section as seen in 1865, and he 



