THE GEOLOGIST. 
its own ink — an honour which this predaceous mollusk could never 
have contemplated. 
The quarry at Dumbleton, a little further round the hill to the east, 
affords a similar section ; but, if anything, the fossil-insect-bed is 
thicker there. As our remarks in this article refer solely to the geology 
of Gloucestershire, it would bo out of place to say much about similar 
deposits elsewhere; but we may just observe that this limestone, with 
the like fossils, has been traced in other counties, especially in Somerset- 
shire, where it has yielded to the energetic researches of Mr. C. Moore, 
ofBath, a rich harvest of organic remains. It may be noticed also at 
Gretton, where a fine specimen of a large fish, a species of Pachycormus,* 
was not long since procured ; and wo have detected it, though much 
reduced in thickness, being scarcely an inch thick, at Churchdown Hill, 
one of the outliers before alluded to between Gloucester and Chelten- 
ham. In all probability, therefore, it will be discovered wherever the 
upper Lias itself is present, and the extension of so thin a calcareous 
band, characterized by nearly similar fossils, over a very considerable 
area, is a fact worthy of attention. The collector may search over a 
good deal of this limestone without success, and yet he must never 
despair, for, when we discovered the fine dragon-fly above-mentioned, 
it so happened that a geological friend had broken up a large block all 
but a small fragment, and in this the nearly perfect ^Eshna was lying, 
with its expanded wings spread out in their natural position of flight, 
or as if laid out with all the skill and care of an accomplished 
entomologist. 
"We must now proceed to give some account of the Marlstone on 
which the upper Lias rests in this county. The upper portion consists 
of a rough, very hard stone, of a blue colour internally and of a brown 
colour externally ; the lower part is more sandy, with masses of sand- 
stone and iron-nodules. It is to obtain this rock that the upper Lias 
clay is quarried, as it forms a useful stone for walls and roads, although, 
owing to the introduction of the mountain-limestone from Bristol, it is 
not so often employed as it used to be. It presents a very difl'erent 
lithological aspect to the muddy deposits above and below it ; and, from 
its indestructible nature, it forms a very good geological horizon in this 
and most other districts where it prevails. It abounds in marine shells, 
* Many species of this curious genus Lave been met with at Whitby, and in 
the upper Lias at Ilminster. R.P.B. 
