WATSON — THE HEMATITE DEPOSITS OF GLAMORGANSHIRE. 245 
in South "Wales," the tlolomitic conglomerate is classed with the 
poikilitic or new red sandstone series, and a lithological resemblance 
is pointed out between this rock and consolidated beaches, tho 
resemblance being further traced in their mode of occurrence. Messrs. 
Buckland and Conybeare, also, in their notice of the south-western 
coal districts of England, observe that the conglomerate "generally 
forms a thick bank or talus near the base of those hills from the 
debris of which it has been derived ; while at a distance from them 
it grows thinner, and at length wholly disappears." But, without 
actually dissenting from the presumed beach-origin of the conglo- 
merate, I submit that the recent mining excavations in the neigh- 
bourhood of Llantrissaut and Llanharry, as well as the openings 
and sections at Newton Nottage, exhibit so much evidence of former 
denudation, that there is strong reason for believing that the patches 
and thin coverings of the magnesian rock now presented to us, are 
mei-ely the remains of a thicker formation, which has been attenu- 
ated to its present condition by aqueous causes ; and, following up 
this view, there is nothing, in the absence of palasontological grounds, 
to show why this rock, which is notably magnesian in its composition 
should not be the representative of the magnesian limestone of true 
Permian age in the North of England, and be wholly unconnected in 
time with the overlying sands and mai'ls at the base of the lias. This 
reasoning seems further supported by the frequent cases of inicou- 
formability in the position of the latter group of rocks. In the 
absence of organic tests, it is fair to assume, all other things being 
equal, the contemporaneity of formations lithologically related, though 
not identical. 
The outliers of the lias, and the scooped-out surflxce of the dolomite, 
where expo.sed in section, and where the hollows are seen filled with 
drift-gravel, mark periods of destruction. And to these we have 
additional witnesses in the loose blocks of the conglomerate which 
fret the surface of such situations as Newton Nottage Downs, and 
the blocks of fine soft pinkish-white argillo-quartzose stone which 
occur scattered over the western part of those downs.* If we follow 
* This rock, mostly in a disintegTated state, often occupies hollows in the lime- 
stone, where it is considered to be in sitH, and it is questionable whetlier it docs 
not belong to the Millstone-grit or its equivalent. In North Staffordshire, the 
