128 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



France, south-east of England, and south of Belgium, it is evident 

 that dry land existed near the first two of these tracts ; for in the 

 English series there are several beds of lignite, and fragmentary * 

 remains of vegetables are dispersed in abundance through many of 

 the strata ; and in the. French series are found the remains of plants, 

 of land and freshwater shells, and of land animals. There is, however, 

 a diiference in the floras, which renders it not improbable that these 

 two land- areas were not connected ; for the French flora, which is 

 not large, is the more tropical, consisting chiefly of some species of 

 large Palms ; whereas the English flora, as far as we can judge from 

 very imperfect indications, exhibits apparently a more varied vegeta- 

 tion, but one of a different character. (If the leaf-beds of Alum Bay 

 and of Bournmouth should be found to belong to the Bracklesham series, 

 then we have species related to laurel, fig, maple, yew, zamia?, &c.) 



Supposing, therefore, such to have been the distribution of land 

 and water, we see a cause why, notwithstanding the presumptive 

 evidence of a common sea, the deposits going on in that sea being 

 derived from two lands, there would be, in all probability, a difler- 

 ence in the character of the coast-sediments f . 



Passing upwards to the third division of the Calcaire grossier, 

 there is a rapid increase in the number of sestuarine, freshwater, and 

 land shells ; leading to the inference, not so much that the French 

 area w-as rising, as that the sestuary, or gulf, in which the Calcaire 

 grossier was accumulating, was gradually silting up ; whilst in the 

 English area a continued subsidence preserved the depth of sea and 

 kept up the marine population. [See note § at p. 134.] This distinction 

 attains its maximum in the upper part of the Calcaire grossier, which 

 seems to be almost entirely fresh water, whereas the upper beds of the 

 Bracklesham series continue to exhibit purely marine characters. 



That these deposits were continuous during the Paris Tertiary period 

 is in accordance with the sketch given of the structure of the Calcaire 

 gi'ossier in the preceding pages, where it is shown that the resemblance 

 in mineral structure of the French to the English series increases 

 from east to west, or as the French series ranges towards the English 

 area ; at the same time that the differences diminish in the same di- 

 rection. Thus the beds of mixed green sands, thin at the base of the 



* Many of the leaves, both in the French and English stiata, are extremely well 

 preserved, and were evidently carried but a short distance out to sea. 



t Still, admitting the operation of all these varied geographical and structural 

 conditions, it may be a question, although tliey may account for certain generic 

 differences in the French and English faunas, whether, on the other hand, such 

 extremes of conditions may not also have modified, to a greater extent than is 

 at present admitted, the form and size of the same species in the different areas, 

 and have been the cause of extreme specific differences. Looking at the separate 

 marine faunas of the Calcaire grossier and of the Bracklesham Sands, we find a 

 certain nundjer of species common to the two, but a far larger proportion pecu- 

 liar to each area. Such, necessarily, must be the case, to a certain extent, in 

 sea-beds so differently constituted ; nevertheless we cannot fail to remark on the 

 fact, that, even where t'lere is no relation in species, still there is often a marked 

 concordance in genera, — in many cases the species of various genera existing in 

 each area in the same relative proportion : thus, amongst others, tiie following 

 11 genera are in nearly equal force in both countries, nevertheless out of the 



