Correspondence — Mr, H. G. Seeley 189 



claiming to make known the existence of DaJcosaurus in England. I 

 trust I shall not appear wanting in courtesy in noticing the paper now, 

 instead of waiting till it is published in full. But as I should then 

 have no more or less to say, I have thought it better to make known 

 the fact that DaJcosaurus has already been chronicled as an English 

 fossil, so that when Mr. Wood-Mason publishes his paper, he may 

 withdraw his claim to be its first discoverer. 



In the Woodwardian Museum occur vertebrae, limb-bones, and 

 teeth of a reptile, for which I had used and still use the name Dinoto- 

 saurus ; and, in a controversial writing on the Potton sands, I had re- 

 ferred teeth (in no way to be distinguished from those in the Kimme- 

 ridge Clay) to the same genus. My friend, Mr. Walker-, soon after 

 found that these teeth, which he had originally referred to as of 

 crocodilian character, were similar to those in the British Museum, 

 for which Quenstedt had used the name DaJcosaurus, and in his 

 next paper in the Annals of Natural History, 1866, and in the Bri- 

 tish Association Eeports, he chronicles the DaJcosausiis as an English 

 fossil, and acknowledges the assistance of Mr. Henry Woodward in 

 its determination. It also was found in the beds at Wicken (Up- 

 ware), and duly enumerated in a paper on that locality by Mr. Walker 

 in 1867, in the Geological Magazine, p. 310. 



It has been known to me for several years in several species, as 

 characteristic of beds from the base of the Oxford Clay to the sands 

 over the Kimmeridge Clay. Hakry Gr. Seelet. 



WoowAKDiAN Museum, Cambridge. 



"MIDDLE DRIFT" GRAVEL AT LOPHAM FORD. 



SiE, — My friend Mr. Gunn originally pointed out to me the in- 

 terest attaching to Lopham Ford, as a crucial test on the question of 

 denudation. He now asks, " how, supposing the valley of Lopham 

 to be attributable to either pluvial or fluvial denudation, supj)osing 

 the watershed to have been ever (? always) on that spot, could the 

 magnificent bed of valley gravel have been deposited on the bank, 

 near the ford and the watershed ? " 



What will he say, when I reply that there is no such bed of 

 valley gravel there at all ? The gravel seen is the " Middle Drift," 

 in which the valley is excavated. I examined it carefullj^, and came 

 to that decided conclusion. As corroborative evidence I found in it 

 a bed of Avhitish sand, containing abundance of the same minute 

 organisms from the Chalk, which are so plentiful in the Glacial sand 

 at Firgrove pit near Norwich, and in the railway cutting near Wells. 

 These could hardly be abundant in a river-gravel in a valley not 

 cut through the Chalk. 



I need not reiterate that I do not attribute the excavation of this 

 valley to pluvial or fluvial, but to Glacial action. The contorted 

 condition of the superficial beds, or " trail," is extreme^ marked in 

 the gravel pit on the Suffolk side at Eedgrave. — 0. Fisher. 



Harlton, Cambridge. 



