MIDDLE LIAS : TILTON. 237 
works. The digging of the ore has however been abandoned 
during the last three or four years (1889). Probably the crinoidal 
beds contribute to the poorness of the ore, although in places they 
have become decalcified. No doubt the best ore occurs where the 
beds come to the surface, and probably they could not be worked 
to advantage beneath any great thickness of clay. 
Prof. Judd gives the total thickness of the Rock-bed as 
18 ft. 6 in., a little in excess of my measurement at Tilton, but 
coinciding with that of Messrs. Wilson and Crick. 
At the east end of the village of Billesdon, two brickyards, 
one on either side of the old coach-road from LTppingham 
to Leicester, furnished a valuable section of the strata about 
10 feet below the Rock-bed ; and this is described as follows by 
Prof. Judd : 
fRock-bed. 
| Light-blue clays with bands of sandy 
Middle Lias -^ ironstone (few fossils) - - about 30 feet. 
I Dark-blue clay with septaria (numerous 
[_ fossils) - - - - 15 feet seen. 
The upper part of the series appears to be very destitute of 
fossils, with the exception of a few fragments of Belemuites. 
Towards its base, however, the clay yields large flat septaria, some 
of which decompose by exposure to the air, and assume a reddish 
brown colour, rapidly falling to pieces. These septaria yield 
numerous organic remains. The blue clays at the base are some- 
times very micaceous, and the septaria contain in their fissures 
Specular iron, Zinc-blende and Pyrites. The following fossils 
were obtained by Prof. Judd : 
Pecten aequivalvis. 
Modiola scalprum. 
Goniomya. 
Ammonites margaritatus (abundant). 
Belemnites paxillosus. 
Plicatula spinosa. 
Lima pectinoides. 
A brickyard at Rocartj south-west of Whissendine, noted by 
Prof. Judd, showed a good section of blue micaceous clays, 
yielding a fauna similar to that above mentioned. Cardium 
truncatum was especially abundant in the septaria.* 
At a brickyard between Somerby and Ouston, Prof. Judd 
noted the following section : f 
Soil. 
Light-coloured clay only partially ex- 
posed. 
Band of ironstone - - - 6 inches. 
Blue, highly -micaceous, and pyritous 
Middle Lias -<( clay - - 3 to 4 feet. 
Blue, sandy, calcareous and highly- 
micaceous rock, crowded, in places, 
with fossils - - - 2 feet. 
Clay with bands of septaria - - 21 feet to 
bottom of the pit. 
* Geol. Rutland, pp. 69, 70. 
t Judd, Ibid., p. 67. 
