FOREST MARBLE. 303 



the series. The beds rest conformably on the Great Oolite in 

 Gloucestershire and Somersetshire, and on the Fuller's Earth in the 

 southern part of Somersetshire and in Dorsetshire. 



The lowest portion of the Forest Marble is sometimes dis- 

 tinguished by the name of the Bradford Clay. The shelly lime- 

 stones are largely made up of comminuted shells of Ostna, Pecten, etc. 



The Mollusca include Ostrea Soiverhyi, Pecten vagans, P. lens, 

 P. annulatus, Trigonia Moretoni, Cyprina Loweana, Lima cardii- 

 forniis, L. duplicata, as well as some Gasteropods. The Brachio- 

 pods include Tcrehratiila rnaxiUata, Waldhcimia digona, W. cardium, 

 Rhynchonella varians, R. concinna, R. obsolela, etc. Most of the 

 species are, however, identical with those found in the Great 

 Oolite and Cornbrash. One Ammonite, A. discus, has been re- 

 corded from Tetbury. The Echinoderms include Apiocrinus Parkin- 

 soni (jvtundus), and species of Acrosa/cnia, Echinohrissus, etc. Corals 

 and Sponges are not abundant. The oldest known British Crab, 

 Palceinachus longipes, has been obtained from the Forest Marble of 

 Malmesbury.^ Palatal and other remains of the Fishes Lepidotus 

 and Strophodus, and bones of Saurians, are occasionally met with. 



Ripple-marks, worm-tracks, and other curious trailings abound 

 on the surfaces of some of the thin beds of calcareous sandstone.^ 

 Lignite is abundant in the limestone beds. Hence the beds were 

 evidently deposited in shallow water, not far from land. 



Bradford Clay. 



This is a deposit of pale-grey or yellowish-grey marly clay, some- 

 times containing seams of limestone and laminse of grit, identical 

 in character with beds in the Forest Marble. It was originally 

 termed the 'Clay over Upper Oolite' by William Smith, as it rests 

 in places on the Great Oolite ; its fossiliferous character, however, 

 caused it to receive a separate name from its occurrence at 

 Bradford-on-Avon. Lonsdale, to whom we are indebted for the 

 first particular account of the Bradford Clay, regarded it as simply 

 a portion of the Forest Marble, and the same view was taken by 

 Prof. Hull.^ 



The thickness of the Bradford Clay is about ten feet in the 

 immediate neighbourhood of Bradford, but it may be somewhat 

 thicker at Farleigh. The fossil-bed to which it owes its import- 

 ance occurs at the base. Where the Great Oolite has disappeared 

 south of Frome, the Bradford Clay and Fuller's Earth come 

 together, and it is not easy to separate the two ; while, on the other 

 hand, where the Bradford Clay is wanting, it becomes in some 

 localities difficult to distinguish the upper beds of the Great 

 Oolite from the lowest of the Forest Marble. 



Fossils were noticed early in the present century by the Rev. 



^ Dr. H. Woodward, Q. J. xxii. 493. 



^ G. P. Scrope, Proc. G. S. i. 317, and Journ, Roy. Inst. i. 538. 



' T. G. S. (2), iii. 255, and Hull, Geol. Cheltenham, p. 69. 



