52 
DOLOMITE. 
The fossils of the limerock, which are subsequently 
to be spoken of generically, are distributed pretty 
generally through out; many spots however, exhibit 
them very sparingly, if at all, while others on the 
contrary, are richly bedecked with these forms. The 
most ordinary sort which the collector encounters, 
is the zoophytic , to which in fact, many spots are 
altogether limited in respect of animal reliques, 
whilst again some sites abound in shells, beyond 
ivliicli they are not noticed , and again, in regard of 
these shells, univalves are limited to some spots, 
and bivalves to others. Certain other places, abound 
so greatly with crinoidal relics, as to cause the 
rock containing them, to be as it were encrinital 
limestone, that beyond Millbay towards Stonehouse, 
being an example. The looser kinds of stone, are 
usually the most fossiliferous, and both in lime and 
slate those parts of the rock which approach the 
surface.* 
At Yealmpton the limestone is surmounted in one 
direction by dolomite , or limestone impregnated 
with magnesia; it forms on the surface, crags, (there 
termed “ tors”) which are extensively subject to 
erosion by weather; it is thicker towards the centres 
of the small hills which it covers, than towards their 
borders ; at the centre also, it mixes greatly with 
the common body of the marble, rendering the rock 
partly dolomitic, while, towards the borders, it is 
pure, highly crystalline, and so beautifully coloured 
as to have been used by statuaries. So far as I have 
yet experienced it is not fossiliferous. It appears 
in small patches in some few other spots of the 
neighbourhood, also at one part of the rock at Cat- 
* It is presumable, that prior to the solidification of our rocks, 
the animals occupying the fluids, accumulated greatly towards 
the surfaces, and thence, are now found as fossils in the loose 
rubbly head-stone. 
