90 
LOWER OOLITIC ROCKS OF ENGLAND : 
stone and Shales, and on the Millstone Grit : while near Mells it 
reposes on the Coal-measures and on the Dolomitic Conglomerate. 
In places, as near Dean, north of West Crantnore, where fossils 
are absent, it is difficult to separate the marginal deposits of 
Inferior Oolite from those of the Lias :* the former however are 
usually oolitic. 
Near Little Elm and on Nunney Common the top beds of 
Inferior Oolite are sparry and slightly oolitic limestones, like 
Doulting Stone ; the lower beds on Nunney Common comprise 
hard and nodular limestones with ferruginous specks, and buff 
sandy limestones with a few fossils, Nautilus, Terebratula, &c. 
FIG. 37. 
Section on Nunney Common, near Frome. 
V 
2. Inferior Oolite. 
1. Carboniferous Limestone. 
The beds are conglomeratic in places, the matrix being oolitic, 
and containing small pebbles of Carboniferous Limestone. The 
Carboniferous Limestone, on whose upturned edges the Oolite 
rests, has been planed off to an apparently even surface. (See 
Fig. 37.) 
Long ago it was remarked by Sir H. T. De la Beche, that 
"Not only is a large portion, of the area, wherein the Inferior 
Oolite is seen to rest on the Carboniferous Limestone, observed 
to have presented a marked even surface, viewed on the large 
scale, for the deposits of the former, but, throughout, this surface 
has been drilled into holes by lithodomous animals, which must 
have existed in the seas at the commencement of the Inferior 
Oolite. The holes, which were observed by Professor John 
Phillips in 1829, are of two kinds, one long, slender, and often 
sinuous, extending several inches into the Carboniferous Lime- 
stone, the other entering that rock a short distance only. In the 
former we find traces of shells, in the latter \ve often discover 
them, in the situations in which they lived. In both holes we 
find the matter of the Inferior Oolite, which entered them from 
above at the time of its deposit. In some places the shells of 
oysters may be observed attached to the surface of the Carbo- 
niferous Limestone on which the oysters lived, and these are 
occasionally pierced through by the borers, which found such shells 
remaining on the rocks after the animals which constructed them 
had died, as we now observe on many sea-coasts. On the top of 
the hill between Holwell and Leighton, oyster shells, of the date 
of the Inferior Oolite, adhering to the old surface of Carboniferous 
* See also Conybeare and Phillips, Geol. Eng. and Wales, p. 255. 
