13 



He notices that these masses of Drift closely resemble those he 

 had already mentioned in the counties of Bucks and Bedford ; 

 but it is evident that the older river-gravels containing Mam- 

 malian remains are here still confounded with the true Diluvial 

 or Glacial deposits. 



1837. In a paper on the Geology of Suffolk by Mr W. B. 

 Clarke, Geol. Trans. 2nd Ser. Vol. v. p. 8G5, the Diluvium is 

 divided into three classes — (1) Glay, (2) Gravel, (3) Erratic 

 blocks. Under the head of Diluvial Clay he says, "This deposi- 

 tion covers a great portion of the county, and extends into 

 Norfolk, Cambridgeshire and Essex ; a large portion of the clay 

 is of a yellowish hue, but the greater part is blue." He describes 

 its general distribution, and notices that its western extension is 

 limited by a line drawn through Haverhill and Newmarket ; 

 The gravel he regards as less generally diffused than the clay, 

 sometimes lying underneath it, but often mixed up with it; and 

 he considers the river valleys to have been excavated through 

 both clay and gravel. 



1838. " On the Drift from the Chalk and the Strata below 

 the Chalk in the counties of Norfolk, Suffolk, Essex, Cambridge, 

 &c." — is the title of a paper by Dr J. Mitchell in the Proc. Geol. 

 Soc. Vol. III. p. 3 ; but only an abstract is there given. He 

 apparently described the Drift deposits, noticing the prevalence 

 of Boulder Clay, which he says is sometimes overlaid by sand 

 and gravel, and sometimes contains or rests on such deposits. 

 In Cambridgeshire he mentions Ely and the country between 

 Caxton and Arrington, noticing the enclosed transported rocks, 

 and concluding that the materials came from a point East of 

 North, derived in part from Scandinavia and in part from the 

 destruction of strata which once occupied the site of the 

 German Ocean. 



1844. A notice of the occurrence of Land and Freshwater 

 shells with Bones of extinct animals in the Gravel near Cam- 

 bridge, by Rev. P. B. Brodie, occurs in the Trans. Camb. Phil. 

 Soc. VIII. p. 138. He describes the section then exposed in the 

 Barnwell gravel-pit as exhibiting alternating layers of fine white 

 sand and pebbly gravel, resting upon a thin bed of brown clay, 

 the whole thickness amounting to about 20 feet. He says, 

 "The stratum in which most of the shells occur is composed of 



