2I00RE ABXOP^IAL SECONDARY DEPOSITS. 497 



and fragments of bones of extinct mammalia of the Postpliocene 

 jDeriod, wliich must have been brought away from the gravels b}' the 

 "water in its passage through them to the surface. 



2. The Ammonites- Bucklandi Beds. — The Ammonites- BucMandi 

 beds of the Bath sections are about forty in number, but vary in 

 thickness in almost every quarry. The uj)per beds are usually 

 brown ; but they are followed below by a series of irregular beds, 

 with clay partings of a deep-blue colour, all of which, have evidently 

 in their times been eroded by water. These rest on the " AVhite 

 Lias," which is invariably present, but, owing to the interposed 

 beds just mentioned, is not often reached. It is seldom that any 

 section exceeds 25 feet in depth. The beds at \ye3ton are most 

 largely worked, and afford an abundance of the organic remains of 

 this horizon, the list being given below. The Bath and Mangots- 

 field Eailway passes tlirough. the middle of the Weston quarries, and 

 has opened up their succession from the Ammonites- BiLcJclandi beds 

 through the " White Lias " and Avicula-contorta beds to the Upper 

 Marls of the Keuper. 



The section in the Saltford Eailway-cutting affords a fine exposure 

 of these beds. This section was carefully prepared by my friend 

 William Sanders, Esq., E.E.S., and has been given by Dr. Wright in 

 his paper " On the zone of Avicula contorta, and tbe Lower Lias of 

 the South of England," in the Society's Journal, vol. xvi. p. 399. 

 In this section the Ammonites- BucTclawli beds, with associated A. 

 angidatus, Lima gigantea, Ostrea arietis, and an abundance of 

 GrypJicBci incurva, are seen resting immediately upon the Ehsetic 

 mite Lias. 



Tbe litbological distinction between the thick -bedded cream- 

 coloured "Sun -bed" of the White Lias and the unconformable 

 Ammonites- Bu.cTdandi beds is so marked as to be perceptible to any 

 geologist, however rapidly he may be passing by train through the 

 cutting, at its eastern end. 



In the Weston quarries a bed called the *' Gutter Bed " shows in 

 its weathered edges many of the Gasteropoda of the Cote d'Or sec- 

 tions. This bed is close below the " Eed Bed " in the same quariies, 

 containing an abundance of Ammonites BucMandi, above which also 

 the same Gasteropods pass. A thin but very persistent bed of in- 

 durated marl occurs at the top of all the sections, which will be 

 again referred to in describing the section at Keynsham. 



List of Organic Remains from Weston, Bath. 



Spirifera Walcottii. \ Lima duplicata. 



Terebratula punctata. | Ostrea arietis (0. multi 



stranguiata, Martin. \ costata, Terq.). 



Anomia irregularis, Terq. intusstriata. 



r- peHucida, Terq. j Hassica. 



Avicula inrequivalvis. I irregularis. 



infraliasina, Martin. I Pectcn Pollux, JJ' Orb. 



Grjphrea incvu'va. j sublacvis. 



Inoceramus. , sp. 



Cytherella aspera, Jones. \ Lima gigantea. Plicatula Hettangicnsis, 



Hhyncboaella variabilis, i Hernianni. | Terq. 



VOL. XXIII. rART I. 2 m 



PlantjTe, sp. 

 Foraminifera, sp. 

 Montlivaltia Sinemurien- 



sis, ly Orb. 

 Echinodermata, sp. 

 Sorpula. 



Cytliere. 



Normania mimdula, Jones. 



