8 
THE LOWER LIAS OF KEYNSHAM. 
fossil forms. His first object was achieved by a general 
account of the fossils found in the Lower Lias, without any 
need for assigning each to its exact relative position ; and 
the second, by the careful collection and examination of speci- 
mens (chiefly of gastropods) from the rich fossil beds of the 
Angulaiits and Arietes zones. 
So far as we are able to judge, the two exposures in the 
area to which Moore devoted his attention are those marked 
3 and 4 on our map. The difficulty of exactly fixing the 
localities arises partly from the absence of any map to 
accompany his text, and partly from the evident fact that 
lower beds were exposed at the time of his work. 
In the Survey Memoir, the exposures described clearly 
include most of our sections 1 to 8, though it is again obvious, 
from the list of fossils, that lower beds were then exposed 
than are shown at the present time. There is, however, no 
attempt made to assign the fossils to their relative vertical 
positions, but merely to enumerate those of most common 
occurrence in the district. 
The account of our work will be best introduced by a very 
brief statement of the few facts we have been able to gather 
concerning the rocks intervening between the upper clays of 
the Lower Lias and the limestones of the Inferior Oolite. 
The mere fact that there are no stone quarries in any Lias 
rocks above the Arietes Limestone is sufficient evidence that 
the middle Lias contains no hard rocks at all comparable in 
thickness with the marlstone rock of other districts. 
On the other hand, the sands of the Midford Sand Series 
are well shown in many places, and notably on Jay Hill, east 
of Bitton Station, where they are somewhat extensively 
worked. In the quarries on the top of this hill the sands 
contain several hard layers, and, in the lowest of these, badly 
preserved ammonites of Upper Liassic facies occur, together 
with abundant specimens of a small sharply ribbed Rhyn^ 
