338 LAMPLUGH : THE NEOCOMIAN CLAY AT KNAPTON. 



Amm. knaptonensis being quite convincing on this point, while most 

 of the other species yield confirmatory evidence. None of the above- 

 mentioned species occur in the lowest beds of the Speeton Clay, 

 i.e., in the zone of Bei. lateralis. 



Then, the presence in one of the pits of the layer of phosphatic 

 nodules mentioned by Professor Judd can no longer be regarded as 

 proof of the horizon being that of the Speeton ' Coprolite-bed,' since 

 I have recently shown that these nodules are not confined at Speeton 

 to ofie horizon, but are abundant at not less than //^r^(? different levels ; 

 namely, at the base of the zone oi BeL lateralis (^ the Coprolite-bed'), 

 at the base of the zone of Bel. jaculum (' the Compound Nodular 

 Band'), and in the passage-marls at the base of the Red Chalk. 



Now, judging from the position of the seam at Knapton with 

 respect to the chalk, and from the fossil-list as given above, I am 

 inclined to think that if the Knapton bed is to be correlated with any 

 of the above-mentioned bands of the Speeton section, it should be 

 with the last-named, viz., that in the marls at the base of the Red Chalk. 



Thus, an examination of all the evidence now available goes to 

 show that the Knapton Neocomians represent chiefly the upper 

 portion of the Speeton section, and that there is no proof of their 

 supposed unconformability with the Chalk at this locality. It is 

 nevertheless certain that the Chalk rests upon the upper members of 

 the Jurassic only two or three miles further westward. It was 

 suggested in my paper on the Speeton clays that the Neocomians 

 may thin out and disappear against the old pre-cretaceous anticline 

 which has its crest in the neighbourhood of Pocklington and Market 

 Weighton (where the Chalk now rests upon Lower Lias), and that the 

 Chalk passes off them by simple overlap, though overstepping the 

 Oolites beyond. This view still seems to me the most probable one, 

 but can scarcely be considered safely established until more positive 

 evidence is forthcoming — and for this we must wait. 



[An interesting confirmation of the view advanced by Mr. Lamplugh 

 is furnished by the following passage from Young and Bird's Geological 

 Survey of the Yorkshire Coast, pubHshed in 1822, when the Knapton 

 pits were still open. ' In one of the clay pits at Knapton, we see the 

 junction of the shale with the red and grey chalk. The clay, where it 

 joins the chalk, is soft and plastic ; and this also is the case with the 

 lower part of the chalk. The two substances are partly blended 

 together ; the soft chalk, which occurs here of both colours, approach 

 ing to the state of red and grey clay ; while the clay that is next the 

 chalk is somewhat impregnated with calcareous matter, and is almost 

 divested of its schistose quality.' (Op. cit. p. 58). — A.H.]. 



Naturalist, 



