WATSON — ^THB HEMATITE DEPOSITS OP GLAMORGANSHIKE. 247 
they occupied when alivo. Yet in the district I am desci'ibing, such 
testimony can be found, and the date, geologically, of the period when 
those elevations occurred which in all probability gave aiTangement 
to the present surface of the land, is most singularly revealed to us. 
Mr. David Rees, of Neath, discovered some time since some modern 
littoral shells among the " attle " from a lead-vein which traverses the 
crop of the limestone at the Llantrissant Lead-w orks, from which place 
the shore now lies upwards of ^eighteen miles distant. .The specimen, 
which is in my possession, is figured on the adjoining page (PI. IX.) 
from a beautifully accurate drawing by Mr. S. J. Mackie, and displays 
a limpet shell (^Patella vulgata) with two barnacles {Balanus balanoides), 
in the position in which they adhered to the rock at the time when 
the back of the vein was washed by the waves ; the lower part of the 
specimen — a piece of confusedly crystallized cax'bonate of lime, in fact, 
an ordinary veinstone — is spotted with little masses of galena, one 
or two of the crystals of which may be seen in the cut. It would 
be leading fi'om the purpose of this paper to do more than remark 
that this species of mollusck {Patella vulgata) as well as the cirri- 
pedes {Balani), are animals inhabiting the tidal zone, and that, 
therefore, the limestone-ridge from which the specimen came must 
have fringed the shore, as does the same rock now near Newton, 
where the " backs " of lead-veins may also be seen at ebb-tide^ 
encrusted with the same description of shells. By reference to any 
good geological map of the district, it wiU be seen that the point 
marked Llantrissant Lead-works lies apparently on the conglomerate, 
but the veins which are close by are found really in the limestone 
which has been exposed by the denudation of the thin cap of conglo- 
merate. It follows from this fact, that, on the evidence of the shells, 
the mass of land lying to the south, and occupied chiefly by lias, was 
probably submerged until a very recent period, and that much of 
the present disposition of the gravel-beds, as already remarked, was 
given to them during the final elevation of the land. 
But if thus much of elevation and denudation of the land has 
occurred, it is obvious that we must find evidence of great dislocation of 
strata, — of beds not only bent into simple or double curves, but of 
rents and fissures such as a succession of elevations and depressions, 
with their concomitant disturbances, would be sure to effect. And, 
