198 REV. J. p. BLAKE ON THE 



ginous and sandy masses, of which the two lower are conglomerates, 

 and the intervening beds are more marly and tend to run into 

 cement-stone. Although these alone have been called " Lower Port- 

 landian," some 55 feet lower down another group of sand and sand- 

 stones is met with. A somewhat similar grouping, on a much 

 larger scale, is seen in the section between Emmets Hill and Hen 

 Cliff. My Nos. 10 to 12 are a peculiarly laminated sandy series, 

 which I called " paper slab." Following this is a group of cement- 

 stones and dicy clay, 'Nos. 13 to 19. Then there is a very solid 

 paper slab, followed by papery shales, to correspond to the upper 

 conglomerates, including Nos. 20 to 22. The more mixed material, 

 including a cement-stone, occupies Nos. 23 to 28, and then the re- 

 presentative of the lower Boulogne conglomerate is a massive rock, 

 Ko. 29, below which, indeed, are other more sandy beds at some 

 distance, which may correspond to those in the Kimmeridge Clay at 

 Boulogne. 



The beds thus reckoned in England amount to 244 feet as 

 against 40 feet at La Creche and 50 feet at Portel, which is not 

 far removed from the proportional increase proved in the overlying 

 beds. But we are not without aid from the fossils. It is very re- 

 markable that Exogyra virgula occurs in thousands beneath the so- 

 called " Lower Portlandian," and it extends upwards to the base of 

 the clays overlying the lower conglomerate, where it forms almost a 

 lumachelle ; yet it dies out suddenly. Other small oysters become 

 abundant, and even form beds ; but they take the place of E. virgula, 

 which is nowhere to be seen. In the Kimmeridge cliffs I searched 

 diligently each bed from No. 10 downwards to find out at what 

 horizon this characteristic oyster is first met with. Nowhere could 

 I find it till I reached No. 28, where it is fairly abundant ; and this 

 bed occupies exactly the position where it is first seen in Boulogne, 

 according to the above correlation. The whole series is, unfortu- 

 nately, but feebly fossiliferous ; the most abundant fossil is an Am- 

 monite, which, I think, from its adult characters, must be A. supra- 

 jurensis. If this be so, it is another proof of the correlation. 



I hold it therefore proved, by as good proofs as can be had under 

 any similar circumstances, that the Boulognian episode is of the age 

 of the lower part of the Upper Kimmeridge — that its representatives 

 are not absent from England, but they are not episodal in the 

 typical district at least. In just the same way we have in England 

 no Pterocerian episode as yet discovered, though the lower part of 

 the Kimmeridge is continuous. The existence of this Boulognian 

 episode has misled the French geologists, in spite of their claim to 

 be guided solely by the fauna, to associate these beds with the Port- 

 land rocks, with which they have very little in common, their in- 

 variant fossils being those of the Kimmeridge Clay ; and Dr. Eitton 

 was right when he regarded them as an " accident " in that 

 formation. 



3. Upway. 



The section at this place (fig. 3, PL YIII.) is small but instructive. 



