262 LIAS OF ENGLAND AND WALES : 
Fig. 85.) The Knoll, as at Glastonbury, is formed of the Sands, 
which rest on a platform of Upper Lias. Here pale earthy and 
rubbly limestones, with A. communis, A. bifrons, c., are turned np 
in the ploughed fields, and may be traced on the brow of the 
platform, west of the hill. In a lane-cutting west of East Brent 
church, pale grey and mottled bluish-grey limestone yielding A. 
communis was exposed. The general section is as follows*: 
FT. IN. 
\*-jf je A ("Thin rock-bed (Cephalopoda-bed), and 
M,dford Sands -{ .1 _ about 200 
Upper Lias - Clay with bands of limestone at base - 40 
A/r-^rii T "f Rock-bed and micaceous sands - 80 
\Micaceousshalesandclays - - 130 
In the neighbourhood of Kilmersdon and lladstock, we have 
no certain evidence of Upper Lias, although there is a considerable 
thickness of blue micaceous clay between the stone-beds of the 
Lower Lias and the Inferior Oolite. Where positive evidence is 
obtained, however, the Upper Lias is very thin, and the mass of 
the clays belongs to the Middle Lias : beds that have been termed 
" Marl stone," proving by their fossils to occupy a much lower 
horizon, as remarked by Moore, than the Rock-bed at Ilminster 
and other places. Hence there may be local breaks between 
the Upper and Middle Lias in the area between Bath and the 
Mendip Hills. (See p. 211.) 
Several species of Lcpttena and Thecidium are recorded by 
Moore from beds of Lias that occur in veins and fissures of the 
Carboniferous Limestone at Whatley. 
The Basement Beds of the Upper Lias, with Ammonites bifrons, 
A. communis, Bdenmites tripartitus, &c., have been noticed at 
Dundrv Hill by Mr. Etheridge.f The entire thickness of the 
Upper Lias and of the overlying Midford Sands, appears to be 
reduced to about 10 feet. 
Near Bath the Upper Lias is but poorly represented in its 
calcareous and argillaceous type. The Basement Beds, from 4 to 
6 ft. thick, have been noticed by the Kev. H. H. Winwood at 
Dundas, and again in the railway-cutting near Devonshire Build- 
ing?, Bath.J They yield Ammonites bifrons, A. communis, 
A. crassus, A. serpentinus, Lingula, JValdheimia Lycctti, 
Rhynchonella Moorei, &c. Similar beds, about 12 feet thick, 
were noted by Moore, at Oaks Lane, Upton Cheney. 
These beds of Upper Lias have not been shown on the Geological 
Survey Map, owing to their meagre development ; but it is 
probable that the Upper Lias increases in thickness northwards, 
from Batheaston towards Marshfield. 
* H.B.W., Proc. Bath Nat. Hist. Club, vol. vi. p. 125. 
j- Quart. Journ. Geol. Soc., vol. xvi. p. 21 ; and W. W. Stoddart, Proc. Bristol 
Nat. Soc., vol. ii. p. 30. 
J Proc. Bristol Nat. Soc., vol. Hi. p. 68 ; and Proc. Geol. Assoc., vol. iii. p. 92. 
See also Moore, Proc. Somerset Arch. Soc. vol. xiii. p. 153; H. B. Woodward, Geol. 
East Somerset, p. 115 ; and Phillips, Geol. Oxford, p. 117. 
