372 
THE GEOLOGIST. 
and though tho upper part makes but a poor road-stone, the lower 
affords a tolerable building material, and slabs of large size are sometimes 
quarried. At Norton and Coomb Hill, and still farther on the road 
towards Tewkesbury, and at Brockeridge Common, near that town, and 
thence to Defford, these strata may be traced, and many pits are 
•worked ; and the student, in order to make himself acquainted with 
them, should trace them from the latter place, following the line of 
quarries to Brockeridge. In this part of the series, the greatest number 
of saurian reptiles have been found, even entire skeletons of the most 
frequent species of Ichthjosaiirus and Plesiosaurus, the /. communis and 
P. doUchodeinis. The presence of these marine lizards indicates a 
somewhat different condition of the sea at that period ; and the wonderful 
state of preservation in which they have been discovered, probably 
shows that they were suddenly entombed and rapidly covered up in the 
calcareous mud with which the waters were highly charged. It is a 
curious fact that in all parts of the world where the Lias is present, 
the remains of these formidable reptiles have been met with, proving 
their wide and extensive distribution throughout the sea at that epoch. 
Their fierce and predaceous habits have been already alluded to ; and a 
few observations may now be added with regard to their structure. The 
jaws of the Ichthyosaurus were armed with pointed teeth ; the eyes 
were of great size, protected by moveable sclerotic bony plates, and 
possessed of great and very distinct powers of vision, beautifully 
adapted to the nature of a reptile which inhabited deep as well as 
shallow water, and occasionally, also, basking on the shore. The head was 
unusually large, and the neck comparatively short ; the vertebi te were so 
constructed that they permitted quick and rapid motion, after the 
manner of fishes. The tail was long and tapering, with a vertically- 
placed terminal fin. The movements of the body were ably aided by 
four paddles. Thus, iu all its parts, this creature combined the 
characters of a fish and a reptile. The largest specimens must have 
attained the length of upwards of forty feet, and may truly be affirmed 
t5 have been the most formidable monsters of the ancient deep. The 
be seen elsewhere ; and many fossils may be procured. There is, also, a small 
patch of Lias, still higher in the series, at Pyrton, on the opposite side of the 
Severn, full of fossils; and this spot is particularly interesting, as it exhibits 
the junction of the Lias -with the npper Ludlow rocks, -which are brought up here 
by a fault and crop out on the banks of the rircr a little farther to the west. — 
P. B. B. 
