Remains in the Oolite Series of England and France. 211 



tic series, though frequently not confined to particular portions 

 of that series, even in England and France, still seem as a 

 mass characteristic of it within the limits noticed in this me- 

 moir. The following shells, according to the foregoing list, 

 contained in the oolite, have been noticed in the chalk and 

 green sand: 



1. Terebratula subrotunda. Chalk. Sussex (Mantell). 



2. carnea. Chalk. Suss. (Mant.). Chalk. Paris and Nor- 

 mandy (Al. Brong.). 



3. ovata. Chalk and green sand. Suss. (Mant.). 



4. biplicata. Green sand. Suss. (Mant.). 



5. ■ lata. Green sand. Suss. (Mant.). 



6. ornithocephala. Green sand. Perte du Rhone, Fis (Al. 



Brong.). 



1. Gervillia aviculoides. Green sand. Suss. (Mant.). 



2. acuta. Green sand. Suss. (Mant.). 



1. Cucullae decussata. Chalk marl. Suss. (Mant.). Chalk marl. Rouen 

 (Al. Brong.). 



I. Turbo rotundatus. Green sand. Blackdown (Sow.). 



1. Rostellaria Parkinsoni. R. Sowerbii (Mant.). Green sand. Blackdown. 

 (Sow.). Suss. (Mant.). 



1. Ammonites splendens. Gault. Suss. (Mant.) 



2. — — — —- la?vigatus. Gault. Suss. (Mant.). 

 1. Cirrus depressus. Chalk. Suss. (Mant.). 



1. Exogyra digitata. Green sand. Lyme Regis, abundant (De la B.). 

 1. Mya mandibulata*. Green sand. Devizes and Lyme Regis. 



Whether we are to conclude that the same species occur 

 in the cretaceous and oolitic groups depends on the credit we 

 may consider due to the respective authors cited; in fact, to 

 their ability in determining specific differences ; — no easy task, 

 but I do not see why, with our present limited knowledge, we 

 should determine the question without further examination. 



It has been generally supposed that the rocks of the oolitic 

 series have been deposited in a sea ; and the great abundance 

 and proportion of marine organic remains entombed in them 

 would seem to render this supposition probable. We have 

 no data by which to form any conception of the extent of such 

 a sea. The portion of the world occupied by the oolitic rocks, 

 noticed in the foregoing remarks, is of insignificant extent, com- 

 prised within a few degrees of latitude and longitude. How 

 far the oolitic series may hereafter be found to extend, it would 

 be difficult to say. It is possible that it may merge in some 

 other great rock deposit, or even be considerably developed at 

 the expense of the cretaceous rocks above or the red sandstone 

 rocks beneath. 



It will be remarked that terrestrial plants, lignite, or coal, 

 occur more or less throughout the whole series. May we not 



* Supposed to be Mya mandibula oi Sowerby. 



2 E 2 therefore 



