160 A. M. Davies — Base of the GaiiU in E, England. 



In all these cases, the fossils clearly came from either the actual 

 base of the Gaiilt, or from Gault Clay not far above Lower Green- 

 sand, except in the case of the last but one, and possibly the last. 

 The gaps of 20 miles, without a record, simply indicate stretches of 

 outcrop where exposures are few. The conclusion seems inevitable 

 that along the outcrop from Folkestone, at least to Dorking, the 

 lithological change from ' Lower Greensand ' to ' Gault ' represents 

 a constant time-level, though farther west this may perhaps cease to 

 be the case. 



Let us next take the northern outcrop from Norfolk to Berkshire : 



Locality. 



Authorities. 



Notes. 



Hunstanton. 

 6^ miles. 



Wiltshire, " Red Chalk of 

 England," p. 17. 



^Amm. serratus' in Red Chalk. 



Ingoldsthorpe. 

 20 miles. 



Fitton, loc. cit., p. 316. 



In grey sandy clay. ' Amm. 

 dentatus.'' 



"West Dereham. 

 19 miles. 



Jukes -Browne & Hill, 



Quart. Journ. Geol. Soc, 



vol. xliii, p. 571. 





Upware. 

 7 miles. 



Keeping, Geol. Mag., 



Dec. I, Vol. V (1868), 



p. 272. 



Base of Gault. 



Between Landbeach 

 and Cotteuham. 



9 miles. 



Penning & Jukes -Browne, 

 " Geology of the Neighbour- 

 hood of Cambridge ": Mem.- 

 Geol. Surv., Sh. 51 (S.W. 

 and N.W.), p. 19. 





Haslingfield. 



Ibid., p. 17. 





19 miles. 







Campton, near Shefford. 

 14 miles. 



Price, "The Gault" 

 (London, 1879), p. 29. 





Heath, N. of Leighton 

 Buzzard. 



194 miles. 



A. M. D. 



Base of Gault. With H. 



tuberculatus and Scklonbachia 



inflata. (See below.) 



Thame (brickfield be- 

 tween Railway Station 

 and Thame Park). 



A. M. D. 



Base of Gault. (See below.) 



14 miles. 







Culham. 

 38 miles to Devizes. 



Phillips, Quart. Journ. Geol. 

 Soc, vol. xvi, p. 307. 



Base of Gault. 



' Amm. dentatus.'' 



The specimens from Heath were found in Mr. Bushell's old 



pit, visited by the Geologists' Association in 1897 ^ under the 



guidance of Mr. A. G. G. Cameron. As I understand that the 



pit will soon be closed over, it may be well to give a full list 



^ Proc. Geol. Assoc, vol. xv, p. 184. 



