20 



seem to be masses of re-constructed Boulder Clay, washed of its 

 mud and converted into gravel." When however he ventures 

 to correlate both the Hill-Gravels and the blue Boulder Clay 

 with the contorted Drift, he is in entire opposition to the facts 

 and conclusions, published by Mr S. V. Wood, Junr., in the 

 previous year, 



(3) Concerning the so-called " Fine Gravel of the plains," 

 Mr Seeley imagines that the physical geography of the district 

 demonstrates all these beds to have been of marine or estuarine 

 origin, and comes to the extraordinary conclusion that they 

 correspond to the Upper Boulder Clay and coarse Gravel of 

 Norfolk. At Overton and Whittlesea he says they contain land 

 and estuarine shells ; at Mareh, marine ; at Doddington and 

 Drayton, marine ; while the Barnwell stratum he would refer to 

 an intercalated freshwater band. 



I shall have occasion to show in the sequel that several 

 different series of gravels have here been confounded and treated 

 together under the name of "fine gravel of the plains," 



1867. A detailed paper on the Post-glacial structure of the 

 South-East of England by Mr S. Y, Wood, Junr. ajDpeared in the 

 Quart. Journ. Geol. Soc. Vol. xxiii. p. 394 



In this he argues that "the entire valley system of the East 

 of England originated in centres of arc-like or curvilinear disturb- 

 ance, which immediately preceded the elevation of the bed of 

 the sea from which was deposited the wide-spread deposit of 

 Boulder Clay forming the latest of the Glacial beds of the South 

 of England." 



He illustrates this opinion by sections through some of 

 these post-glacial upheavals, one of which is across the Cam 

 valley from Eversden on the N, to the Chalk Hills above 

 Boyston on the S. and shows the Boulder Clay overlapping the 

 Mid Drift towards the N.W. He does not seem to see however 

 that the disposition of the Drifts in the three sections on p. 402 

 is just as easily explained by the supposition of the pre-glacial 

 existence of the chalk escarpment, as by its subsequent post- 

 glacial upheaval. The facts collected for this essay have led me 

 to take the former view, and I cannot but think that the 

 whole theory of curvilinear elevations rests upon a very slight 

 foundation of evidence. 



