G. F. Harris — Geology of the Gironde. 27 



These are grouped into etages. Nos. 6 to 8, both inclusive, belong- 

 to M. Mayer-Eymar's " Langhien " and No. 9 to the " Helvetien," 

 and although this nomenclature is generally accepted by Bordeaux 

 geologists, M. Fallot points out ' that it is not strictly applicable to 

 the Miocenes of the Gironde. Neither are the Austrian divisions 

 (1st and 2nd Mediterranean etages). The uppermost division of the 

 Miocenes, the Tortonien of Italian geologists, does not seem to occur 

 in the department. 



Langhien. — Above the Aquitanien beds at Leognan, some sandy 

 deposits belonging to No. 6 contain many Echinoderms, having at 

 the base a zone with fish-teeth, etc., notably Notidanus, Lamna, 

 Oxyrliina and Carcharodon megalodon. In the valley of Saucats the 

 mollasse of Leognan is represented at Giraudeau, near Moulin de 

 l'Eglise, where the ferruginous-looking falun contains a very rich 

 fauna. At the present time, however, this locality is rather disap- 

 pointing, no section is to be seen, nothing but a planted field sur- 

 rounded by woods meets the eye, yet the ground is literally covered 

 with fossil mollusca, amongst which I brought away Ancillaria 

 glandiformis (very characteristic of this assise), Proto cathedralis, 

 Volnta rarispina, and Pectunculus cor. 



About half-way between Giraudeau and the St.-Morillon railway- 

 station one leaves the main roach and following a rough cart-track to 

 the southward through the vines for about 200 yards, comes across the 

 fossiliferous locality of Peloua. Here again there is no section, but 

 it is one of the classical localities in the Bordeaux Miocenes, having 

 yielded about 400 species of fossils. At the time of my visit, by 

 good fortune, the most interesting part of the ploughed field was not 

 planted with vines ; if it had been, we should not have obtained 

 permission to visit the spot, and this remark applies generally to 

 many of the most interesting localities in the Bordelais. As it was, 

 I picked up a large number of corals and mollusca. Amongst the 

 latter were Banella tuberosa, Tndicla rusticida, Strombus Bonelli, 

 Melongena cornuta, Potamides plicatus and Pecten burdigalensis. The 

 horizon of the Peloua zone is believed to be about the same as that 

 at Giraudeau. M. Fallot pointed out to me the fact that the Peloua 

 fauna contains almost all the species of Potamides found at Lariey 

 and Moulin de l'Eglise (bed No. 4 of "les couches faluniennes "), 

 to which places I have already referred, and it possesses other 

 affinities linking it closely to the Oligocene, at the same time the 

 general facies is decidedly Miocene. In the absence of sections, it 

 is not easy to say what are the precise stratigraphical relations 

 between the Miocene and Oligocene of the Bordelais, but the 

 pala3ontological evidence certainly proves that the passage from the 

 one to the other is very gradual. 



Zone No. 7 at Leognan is divided into two parts, the lower being 

 a yellow sand, the higher a blue clay, both of which contain 

 numerous fossils. These beds are also represented in the valley of 

 Saucats, the former at Cassagne, the latter at Moulin de Lagus. 

 The last-mentioned place, very close to the village of Saucats, like 

 1 "Esquisse," op. cit. p. 15. 



