﻿JURASSIC AND TRIASSIC BRACHIOPODA. 



107 



Mr. Moore observes that "this species has been figured by Mr. Davidson and Mr. E. 

 Deslongchamps, the latter of whom mentions that the sub-circular ridges in the French 

 specimens are sometimes formed of a double line of granulations. In examples that 

 have come under my observation, the ridge is usually made up of single granulations, and 

 those at times widely separated, but I have no hesitation in placing them under 

 this species." 



Th. triangulare is a common species in the Inferior Oolite of Dundry ; the large 

 valve is, according to Mr. Moore, attached in abundance to Oysters and other shells, in 

 the fuller's earth near Combe Down, Bath. Has been found in the Great Oolite of 

 Hampton Down, Bath. It has also been met with in the Coral Rag, but no specimens have 

 been hitherto recorded from either the Kimmeridge or Portland rocks. According to 

 Mr. Moore it would have made its first appearance in the Lower Lias at Brocastle, 

 Keynsham, in the Middle Lias of Ilminster, and in the Upper Lias at Charter House 

 Mine. Mr. Deslongchamps quotes the species from the Great Oolite of St. Aubin de 

 Langrune, near Caen, in Normandy. 



53. Thecidium rusticum, Moore. Dav., Ool. Mon., p. 15, PI. I, fig. 14; and Sup., 



PI. XIII, fig. 10 ? 



Thecidea rustica, E. Deslong. Mem. Soc. Linn. Normandie, vol. xiii, pi. xiii, 



figs. 12—18 and 20, 1853, and vol. x, pi. v, figs. 

 11, 12, 1855. 



According to Mr. E. Deslongchamps, the interior of the dorsal valve varies very 

 considerably in the shape of its raised septum or ridge, which becomes much more 

 sinuated and dilated in some specimens than in others. 



Th. rusticum has been found in the Lower, Middle, and Upper Lias. In Prance 

 it was obtained by Mr. E. Deslongchamps from the Upper Lias of May, in 

 Normandy. 



54. Thecidium subserratum, R. Tate. Sup., PI. XIII, figs. 11, 12, 13. 



Thecidium subserratum, Tate. Geol. Mag., vol. vi, p. 551, 1869. 



" Shell subquadrangular, attached by the whole of the lower surface of the ventral 

 valve, the front of which is much elevated : area triangular, narrow, hinge-line long and 



