88 LIAS OF ENGLAND AND WALES: 
them identical in character with the white beds at Sutton in 
Glamorganshire, as pointed out by De la Beche.* In both cases 
the beds rest directly on the Carboniferous Limestone (see 
Fig. 43, p. 90), and therefore it can hardly be questioned that 
their characters are due to the same causes. They are in fact 
granular beds of limestone of detrital origin, derived largely from 
the destruction of the Carboniferous Limestone. In some cases, 
moreover, on the Fosse road, north of Shepton Mallet, and again 
in Glamorganshire, as I know from personal experience, it is 
very difficult on a first inspection, to distinguish the thick beds of 
Lower Lias where the clay-divisions are absent, from the Car- 
boniferous Limestone a fact pointed out by De la Beche. 
These beds; have been exposed to a depth of 20 feet in the road- 
cutting leading from Shepton Mallet Church towards Downside, 
and south of the Midland railway; and also in a quarry by the 
side of the viaduct that crosses the road. No marked divisions 
occur in the Aeries, which comprises thin beds of limestone with 
ferruginous specks, passing down into massive beds of hard pa!e- 
ffrey, buff, and white sandy and granular limestone with but little 
clay, and with chips of chert. There is an impei eistent bed of con- 
glomerate 6 inches thick (seen in the quarry), and it is composed 
mostly of chert, with some pebbles of Carboniferous Limestone. 
A few quartz pebbles occur, and they are also occasionally to be 
seen in the ordinary beds of Lower Lias, exposed at Shepton 
Mallet: no doubt they are derived from the conglomeratic beds 
in the Old Red Sandstone of Mendip. 
The lowest beds consist of a shelly rock with casts of Modiola, 
Ostrca liassica, O. multicostata ((metis*), and Lit/todot/ius. These 
soft shelly beds were exposed aUo at Bowlish, where Lima 
occurred abundantly. 
Many other species have been recorded from these rocks. In 
the Museum at Jermyn Street there are specimens of Pecien 
Pollux (or suttoncnsis), Lima tulerculatu, L. pun<-tata, L. 
duplicata, Hinnitcs, and Pecten insiynis, which were. 1 collected by 
Mr. Alfred Gillett. Moore has published a more considerable 
list,t but there has been much difference of opinion about the 
precise identification of some of the fossils, and the same diffi- 
culty occurs with respect to the Sutton and Southerndown species. 
Quite recently, the Rev. II. H. Winwood has obtained specimens 
of Ammonites Johnstoni and Lima gigantea: an interesting dis- 
covery, as the Ammonite has not previously been recorded from 
the white granular limestone of Shepton Mallet. 
The evidence, as in South Wales, is in favour of the beds 
belonging for the most part to the zone of Ammonites phmorbis, 
but including in this locality portions also of higher /.ones. 
The road between Bowlish and Windsor Hill has been ex- 
cavated where the railway crosses it, and hero beds of Lias lime- 
* Mem. Geol. Survey, vol. i. p. 27'J. Auckland and Oonybeare, Trans. Geol. 
Soc., ser. 2, vol. i. p 303. 
t Quart. Jon:-::. Gco 1 . Sec., TO!, xxiii. p. 509. 
