JURASSIC OF THE PARIS BASIN. 



553 



referred, which is, at the same time, proved to be on a much higher 

 horizon than the ordinary Coral Rag of Normandy. 



The section thus concluded at Villerville can be perfectly taken 

 up on the other side of the estuary at Havre ; for the " Trigonia- 

 grit" at the former is simply the continuation of the Calcaire a 

 Trigonies " at the latter, of which the fauna has been so admirably 

 illustrated by Dollfus. These, including the associated marls and 

 other hard bands, up to and including the grey clay over the fossili- 

 ferous grit, are therefore the Kimmeridge passage-beds, as was 

 ascertained by Waagen (35). It is also obvious that by their stra- 

 tigraphical position and by many of their fossils they represent the 

 Astartian beds of the rest of Trance*. Of the overlying beds at 

 Havre little need be said, since their position cannot be otherwise 

 than clear. The beds included between Xo. -I and Xo. 14 of Len- 

 nier's section, the latter being a hard band with many gasteropods, 

 represent Dollfus's " Marne a Pteroceres," and the basal portion of 

 the Lower Kimmeridge of Weymouth. In Xormandy there is 

 certainly much more reason for establishing a " Pterocerian stage, ,J 

 since Pteroceras Poati is a very common fossil both at Yillerville 

 and at Havre, and has associated with it a sufficiently distinct 

 fauna. It is therefore perhaps only due to the imperfect searching 

 of the beds at "Weymouth that a similar fauna has not been dis- 

 covered there. Of the fossils in Dollfus's list which are found only in 

 the Pterocerian beds, the following occur in the Lower Kimmeridge 

 of Weymouth — Amm. decipiens, Pleuromya tellina, P. donacina, 

 Pholadomya acuticosta, and Ostrea solitaria. Only one of these is 

 at all characteristic ; and that is Phol. acuticosta, which, as we have 

 seen, is a constant species in the Virgulian marls, whether these are 

 divisible into two parts or not. In fact the fauna consists almost 

 exclusively of ATyacidye, Gasteropods, and Echinoderms, of which 

 the latter two groups are so remarkable that they could scarcely 

 escape attention if they occurred at all freely at Weymouth. Hence 

 though the beds must correspond stratigraphically, we have no en- 

 couragement in this country to recognize a " Pterocerian" subdivision. 

 Two other fossils may be noted. Avicula cedilignensis occurs in these 

 beds, which may hence be a guide to correlation: and about halfway 

 between the Trigonia- grits and the Gasteropod-bed are bands full of 

 Terebratula Leymerii, with associated nodular beds. It would 

 therefore be perfectly defensible to raise the upper limit of the 

 Astartian to this level, except that E. virgula has already begun to 

 be abundant. The " Ammonite clays " of Dollfus present no points 

 of interest, as they are but poorly seen and slightly f ossilif erous, and 

 they do not attain to the Upper Kimmeridge. 



The only other locality examined in Normandy is the neighbour- 

 hood of Lisieux and Glos, which presents us with a greater develop- 

 ment of a portion of the series seen at Trouville. This locality is 

 included in the general description of Xormandy by Caumont, who 



* This is not the conclusion I arrived at in my paper on the Kimmeridge 

 clay ; and the correction shows the advantage of a personal over a literary 

 acquaintance with the French series. 



