236 LIAS OP ENGLAND AND WALES: 
A trial-boring at Uppingham (1876) commenced near the top 
of the Upper Lias, was carried to a depth of 400 feet, mainly in 
clay, with only thin stone-beds here and there, but the record 
furnishes no clue whereby to distinguish the junction with the 
Middle Lias. 
The Middle Lias has been well exposed in quarries to the west 
of Robin-a-Tiptoes, and again in the railway-cutting near Tilton 
station. In this district Prof. Judd noticed on top of the Marl- 
stone, a bed two feet thick, of " Laminated, ferruginous, sandy 
and marly clay, forming a gradation from the Upper Lias Clay to 
the Middle Lias Rock-bed."* This is the " Transition Bed " 
previously described, and it has been carefully examined by 
Messrs. E. Wilson and W. D. Crick in the Tihon railway- 
cutting, t There it consists of flaggy limestone with its charac- 
teristic Ammonites acutus, but is scarcely separable from the 
Marlstone. 
The section which I noted in the railway-cutting is as follows : 
Soil and Drift sand. FT. IN. 
Upper Lias - Blue clay and shales. 
Transition Bed. 
fGreenish and brownish marlstone, alter- 
Inating in places with seams of crinoidal 
rock and presenting appearances of false- 
Middle Lias. 4 bedding . - about 16 
Micaceous sandstone and sandy shales, 
about 20 
(^Blue clays. 
Messrs. Wilson and Crick have published a list of fossils from 
the Marlstone of Tilton, including the Transition Bed, and this 
includes ihe following species of Ammonites : A acutus, A. 
annulatus, A communis, A. margaritatus, A. ovatus, A. serpen- 
tinus, and A. spinatus. This shows the intimate connexion between 
Middle and Upper Lias, and corresponds with the evidence 
obtained at various points throughout the country from the 
Dorsetshire coast. 
A large number of Gasteropods were obtained from the 
Transition Bed. The Middle Lias sandy shales have yielded Am. 
margaritatus, Cardium truncatum, &c. I obtained Ammonites 
acutus and A. communis from the upper part of the Marlstone, 
and. these species are also recorded by Messrs. Wilson and Crick 
from beneath the Transition Bed. Belemnites paxillosus, B. 
elongatusy Pecten cequivalvis, P. dentatus, and P. lunularis occur 
also. Rhynchonella tetrahedra and Tcrebratula punctata are most 
abundant in the lower beds, where they occur in clusters. 
The lower beds of the Marlstone are less massive than the 
upper, and at the base there are three, more or less nodular, bands, 
of greenish sandy rock weathering brown, the ferruginous stamina- 
resembling the " box-structure" of the Northampton Ironstone. 
The beds are much more oxidized where they outcrop further 
north ; and to the west of the railway there, are old ironstone- 
* Geol. Rutland, p. 68. 
f Geol. Mag. 1889, p. 296. 
