6 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 4, 



Valognes three specimens of the Diadema globulus, one of the most 

 common fossils of the Choin-batard. 



The next point of interest which attaches to these beds is, that 

 they everywhere indicate a break in the continuity of the series of 

 deposits before the commencement of the lias. In Normandy and 

 the Lyonnais the freestone beds become compact, and appear to 

 have been again broken up and furrowed, before the lias was thrown 

 down upon them. There is nothing in common in the faunas of the 

 two deposits; and we have also, as M. de Caumont observes, a di- 

 stinctly marked interval of time separating them. 



In this country the passage from the red marls to the white lias, 

 and again to the lower lias marls, as seen on our southern coast, is 

 not marked by any distinct break, and the most that can be deduced 

 from the appearances thus exhibited is, that a change took place in 

 the conditions under which certain beds were deposited as compared 

 with others below them. 



When a great disturbance has taken place in the earth's crust, 

 the deposits next in succession must occur in every possible relation 

 to those last accumulated, but part of them may remain in the same 

 position as before, and be covered conformably by beds of like 

 mineral character. Such was the case nearly with respect to the 

 red marls and lias marls of other parts of England. In France and 

 some parts of Germany the line of separation is broadly drawn, and 

 in addition to this a change takes place in the infra-liassic strata, 

 which clearly indicates a decrease of depth in the sea in which they 

 were formed. This is very general in France, and Count Mandels- 

 lohe, when noticing some beds of this age in Wurtemberg, describes 

 them as containing great numbers of undescribed littoral shells 

 (^Ampullaria, Trochus, Turritelld), 



The Valognes freestone however, and the equivalent strata else- 

 where, are not without an exact representative in this country. Be- 

 ing some time since at Porlock for the purpose of looking at the curi- 

 ous outlying mass of secondary strata there, I came upon some large 

 blocks of stone, which were being used in building some cottages, 

 and found them composed to a great extent of broken shells, the 

 smaller ones of which alone were perfect, but these in most beauti- 

 ful preservation. The beds from which these stones had been taken 

 I found to be intermediate between the upper red marl and the blue 

 lias shales and limestones ; and they indicate that for some time 

 before the deposition of the lias marl, which is a deep-sea deposit, 

 there existed at that spot conditions which favoured the accumula- 

 tion of vast numbers of molluscous animals. The species are all 

 new, chiefly gasteropodous. 



2. Notes on a Microscopical Examination of the Chalk and. Flint 

 of the South-east of England, with remarks on the Atiimalcules of 

 certain Tertiary and modern deposits. By G. A. Man tell, Esq., 

 LL.D., F.R.S., F.G.S. 



[This paper was withdrawn by the author with the permission of the Council.] 



