346 LOWER OOLITIC ROCKS OF ENGLAND : 
Beaminstcr to Sherborne. 
Leaving the neighbourhood of Bridport and Weymouth, where 
the strike of the Forest Marble is east and west, we find the out- 
crop concealed for some distance by the Cretaceous rocks. About 
a mile north of Bearninster a small area of Forest Marble was 
mapped by H. W. Bristow, and he also observed an inlying mass 
by the village of Rampisham, A specimen of lignite from 
Rampisham, now in the Museum of Practical Geology, shows 
borings of Littiodomus. 
North of this tract we come upon the main outcrop of the 
Forest Marble, and this although displaced and interrupted here 
and there by faults, forms the most prominent of the well-marked 
escarpments in the Jurassic rocks of Dorset and south-east 
Somerset. (See Fig. 134, p. 460.) 
The general section of the strata does not differ materially from 
that exhibited at Eype and Bothenhampton, but nowhere until we 
approach Bradford-on-Avon, has any exposure been observed of 
the Rhynchonclla-bed, though it is probable that a careful search 
in some of the lane-cuttings may reveal its presence. Birts Hill 
and Abbots Hill, south of Pendomer, and the ridge on which 
Hardington stands, form the westerly portion of the main escarp- 
ment. Quarries may be seen here and there in the stone-beds, 
but they exhibit few features that call for special remark. Near 
East Field, Hardington, the stone includes occasional lenticular or 
spheroidal masses of sandy and oolitic limestone. The stone is 
quarried south of Yetrninster, but some of the best material has 
been obtained from openings to the north of Long Burton village, 
south of Sherborne. Here we find from 12 to 15 feet of false- 
bedded shelly limestones, in layers from 2 to 9 inches thick, and 
overlaid by clay. The stone is much jointed and separated by 
partings of clay. The joints in places have been enlarged by 
meteoric agencies, and the spaces are filled with clay. Ostrea 
Soiverbyi is abundant, and species of Pecten, Rhynchonetta, and a 
good deal of lignite occur. 
The thickness of the Forest Marble of Dorsetshire has been 
stated by Bristow to be as much as 450 feet, but this was 
probably based on an estimate given by Buckland and De la Beche, 
who included the Fuller's Earth.* There is reason to believe 
that the formation attains its greatest thickness near Sherborne, 
where it forms the high grounds of Lillington and Gainsborough 
Hills. The following section in the road-cutting at West Hill, 
south of that town, indicates a thickness of about 130 feet. The 
upper portion was measured by H. W. Bristow, and the lower 
portion (subsequently) by myself: 
* Trans. Geol. Soc., ser. 2, vol. iv. p. 29 ; Bristow, in Report Coal Commission, 
vol. ii. p. 456. 
