502 PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



at Shepton and Soutlierndown, and the valves of a species of 

 Chiton. 



5. Sections at Keynsham and Stoufs Hill. — There can be no ques- 

 tion that the quarries of Keynsham are on the horizon of the Am- 

 monites- BiicJdandi beds ; but, notwithstanding, it will be seen that, 

 with those of Stout's Hill in the same district, they afford an im- 

 portant key to the determination of the age not only of the fauna 

 from the Charter House Mine, but also of that from Brocastle and 

 Button in South Yf ales, and, as a consequence, of that also of the 

 beds of Yalogne, the Cote d'Or, and other continental localities. 



At a coal-wharf on the banks of the river Avon, between Keyn- 

 sham and Stout's HiU, there is a quarry in which the basement 

 Liassic beds are present, and in which the lower horizons of the 

 Camel section are repeated, viz. : — ^ 



1. White-Lias, at the base, but not fully uncovered (Insect and Crustacean 

 beds wanting). 



2. Ostrea-beds. Eighteen beds of stone and marl, crowded with the charac- 

 teristic Ostrea liassica and with My a, sp., Cardium Vhili'p'pianum, Terq., Cypri" 

 cardia Bi-oomi, Martin, Cardinia exigiia, Terq., and Myacites : 3 ft. 6 in. 



3. Seventeen more nodular beds of stone and clay, about 5 ft. thick, con- 

 taining Ammonites flanorhis, A. angulatus, A. Johnstoni, Nautilus, Pinna, 

 TJnicardium cardioides, Astarte jpsilonoti, Q^e^ist., Fecten Pollux, and Lima 

 tuherculata. 



4. Thick grey clays, about 6 ft. (divided by several bands of septaria), con- 

 taining multitudes of Echini and bones of Plesiosaurus riigosus, Owen. 



The beds in this section dip very rapidly in the direction of the 

 Ammonites-Buclclandi quarries at Keynsham and pass under them, 

 though the intermediate beds are not shown. 



In the uppermost portion of the A.-BucMandi series there is a 

 thin band, from two to three inches thick, composed of a brown, 

 indurated, laminated marl, interposed between the limestones, 

 over the area of Bath, "Weston, Twerton, Saltford, and Keynsham ; 

 it shows an interruption in the ordinary Liassic deposits, and 

 indicates a precise horizon at the top of the series throughout the 

 district. In this thin bed are many plants, including Araucarites, 

 with remains of Hyhodus, Acrodus, Lejndotus, and the heads and 

 tails of Leptolepis, the body having perished. Avicida incequivalvis 

 is particularly abundant, associated with Ostrea ocreata, Desl., and 

 Ostrea liassica {0. anomala, Terq.); and it is the only horizon in 

 which I have found Anomia iDellucida, Terq. (p. 25. fig. 5) ; the 

 fig. 5 a of that author is also found in this bed, but is apparently a 

 Plicatula. Had the Hybodus-spine figured by M. Terquem, pi. 12. 

 fig. 3, of the '^ Infralias of Hettange," been placed in my hands for 

 a determination of its horizon, I should at once have referred it to 

 this bed, as these species are found therein at Keynsham. 



But the most important point remains to be noticed. This thin 

 bed is interposed between thick-bedded limestones ; and below it in 

 particular are found ih.Q fine examples of Ammonites BucMandi 

 yielded by this locality, and a great profusion of Gryphcm incurva. 

 In the ragged and weathered edges of the beds which enclose this 

 band of marl are to be found; in great part, the fauna described by 



