90 
GEOLOGY OF THE FOURTH DISTRICT. 
The crinoidal mass forms the capping of the terrace every where in the vicinity of Lock- 
port, and is the same in which all the quarries of importance are situated. It varies in texture 
from fine grained, where the nature of the component parts can scarcely be detected, to that 
where the sterns are several inches in length. Where weathered, these stems stand out upon 
the surface in strong relief, forming beautiful illustrative specimens for the cabinet. Plates 
of the Caryocrinus ornatus, and fragments of corals, frequently occur together. The wood- 
cut No. 26 is an illustration from a specimen found near the village. 
26. 
Fragments of Encrinital columns in Limestone. 
These stems lie in the greatest possible confusion, and many of them are much worn. 
Perfect fossils are rarely found in this rock, all the materials having evidently been triturated 
by the waves for a long period, while they formed a calcareous beach or bar rising to near 
the surface of the ocean. 
The succeeding mass contains a great abundance of corallines, some of them in the position 
in which they grew ; others turned upon their sides, or entirely reversed. Many of these are 
in a very perfect condition ; others are partially destroyed, and crystalline matter has taken 
their place. The greater number apparently belong to a species of Poriles of very delicate 
structure. 
In the third division the cavities are more abundant; and we often find, that surrounding the 
edge of these, a portion of the fossil still remaining, marks its former extent. In other cases 
a mass of coral is partially dissolved, with crystals of selenite penetrating it in every direction. 
Again the coral is almost completely blended with the selenite, as if it had been rendered 
