622 Extracts from the Minute Book of the Geological Society . 
Shells, which I believe are univalves, may be seen without diffi- 
culty in a part of the rock of Mount Wise that is uncovered, a little 
to the east of the battery, not far from the path-way that leads from 
the port-admiral’s house to the navy stairs below. These shells are 
of a harder texture than the shells before noticed, and retain less of 
their natural appearance. The contents of this part of the hill 
resemble those of the south-western part of Stonehouse-hill, which 
we shall next describe. 
Immediately on passing the last houses leading from Stonehouse 
to Plymouth, over the hill by the south side, I have found above 
and below the road, detached fragments, lying several feet under 
the present surface, differing but little from the solid rocks near 
them, containing, besides madrepores, many species of univalve 
shells so blended with the surrounding matter, as to form a solid 
mass, so that it has been with difficulty that I have obtained 
from these fragments any perfect specimens of shells. This stone 
is of a dark colour, and is capable of receiving a fine polish, by 
which its shells and madrepores are rendered beautifully distinct. 
I have lately observed the presence of madrepores, entrochi, and 
shells, in the limestone raised from several pits opened on the north 
side of Stonehouse-hill for building the houses in Union-street, 
leading from Stonehouse to Plymouth. Madrepores and entrochi 
are contained in considerable quantity in masses of blue and grey 
limestone mixed with clay-slate, raised from a well at the back of 
the same houses. 
At Mill Bay and Sandy Cove, which connect the west Hoe with 
Stonehouse-hill, the madrepores, tubipores, millepores, entrochi, 
corals, and bivalve shells are in great abundance, and are visible at 
almost every step : particularly where the limestone and clay-slate 
join, and are intimately blended or alternate with one another. 
