328 Dr. FiTTON on the Strata below the Chalk. 



generally, in England, as no more than in a particular and subordinate bed of the Glauco-ferru- 

 ginous sands*. 



7. Gres glauconnieux ; Gres vert. — (Portland-stone and Sand.) 



These terms are applied to green-sand passing into grit, which again passes into a calcaire 

 glauconnieux. Both the grit and limestone are full of green particles : they alternate with beds of 

 sand, and are generally quarried throughout the Pays de Bray : and the gres calcaire is stated to be 

 identical with that observed by M. Rozet, at Mont Lambert in the Boulonnois. Among the fossils 

 are Ammonites ; Crassatella ; Cucullaea ; Ostrea ; Serpula ; Trigonia ; and teeth of the Diodon. 



M. Passy justly expresses doubt whether this grit has hitherto been recognised in England. 

 I believe it to belong to what I have proposed to call the Portland-sand ; the characters and 

 relations of which, though long since generally intimated by Mr. Conybeare, have not hitherto been 

 fully understood in England : and, from my own observation, I have no doubt that some of the 

 concretional masses of the Boulonnois belong to this part of our series. It will be observed, on 

 comparing M. Passy's sections with those in the interior of England, that the lower greenish 

 grit (Portland-sand) of M. Passy f, is not conformable to the beds above; — a fact analogous to 

 the existence of chasms and "gullies", in the Lower Purbeck, and upper part of the Portland 

 strata, in Oxfordshire and Bucks:— supra (111.), p. 218 ; (141.), p. 265; (144.), p. 276, (151.). 



8. Calcaire glauconnieux ; — a limestone composed of fragments of shells, united by sparry 

 carbonate of lime, containing green particles, rolled grains of quartz, and flints of different hues. 

 The fossils include Ostrea gregarea, and other indistinct species ; Trigonia ; and Crassatella, The 

 limestone in this group alternates with grit, and includes a bed of green or bluish marl. The 

 whole belongs to the group between the Portland-sand and the Oxford-oolite in the Lower Bou- 

 lonnois and is represented in England by part of the series on the coast near Weymouth. 



9. Marne et calcaire marneux ; — a Gryphcea Virgula ; Calcaire lumachelle. 



The strata of this group are described as occurring unconformably — (" etendues en couches dis- 

 cordantes"), beneath the ferruginous sands : a statement which accords with the relations of the 

 group to the Upper green-sand, — but not to the sands of Portland. The formation is characterized 

 by Gryphcea Virgula, and some of the beds contain Ostrea deltoidea. On the coast, from Havre 

 towards Henqueville, it occupies a thickness of 30 metres (about 100 English feet), between the 

 chalk and the oolite % ; and it seems to be the equivalent of the series of shale, limestone, and cal- 

 ciferous grit abounding in petrifactions, which connects the Kimmeridge-clay with the Oxford 

 oolite, on the coast of the Boulonnois, and of Dorsetshire. 



10. The lowest strata of the Pays de Bray "consist of blackish compact limestone, like that of 

 " Marquise in the Lower Boulonnois ; — the carboniferous limestone of England : " and these suc- 

 ceed immediately to the group last mentioned. If this be so, the oolitic series, from the Oxford 

 oolite to the bottom of the lias, is wanting; together with new red sandstone and the coal forma- 

 tion : — another point of resemblance to the Lower Boulonnois. 



(168.) Marine deposits coeval with the Wealden. — It is obvious that, during 

 a period of time sufficient for the accumulation of the Wealden, the deposition 

 of matter in the adjacent seas could not have been inconsiderable ; so that we 

 might expect to find, interposed between the strata which then formed the 



* "....que I'argile Veldienne qui contient les coquilles d'eau douce, n'est qu'une couche 

 " particuliere de terrains glauco-ferrugineux d'Angleterre." — p. 256. 



f Passy, p. 272 ; and Plates I. and II. t Ibid., p. 262, 263. 



