16 NOTES ON THE GEOLOGY OF 
Limestone. On the other side of the quarry, where the water 
has percolated to the limestone between the patches of drift, 
the concretionary character of one of the beds is brought out, 
and it weathers to a knobly rock. Near the bottom of the quarry 
there is a bed, about 8 inches thick, in which the difference 
between the concretionary crystalline rock and the more 
aluminous portions is shown by darker and lighter shades of 
grey and brown, producing a mottled limestone like that 
known as the “‘ Anglesey Marble.” 
The top of the Mountain Limestone is sometimes split up by 
sandstones, anticipating as it were the great sandstone series 
above. This may be seen near Llanfair-dyffryn-clwyd, as 
shown in the section fig. 2, 0. 
Here another difficulty presents itself. Owing to the overlap 
of the New Red Rocks, the more porous beds of the under- 
lying Carboniferous are deeply stained with red iron oxide. 
The same things happened in the case of the Knaresborough 
Grits (see WARD) and of the Carboniferous Sandstone of the 
Eden Valley, where the stain has been proved toa depth of 
1zoft. So around the Vale of Clwyd the sandy beds of the 
Carboniferous series are stained by the New Red, and have 
often been thrown in with the New Red. The above-mentioned 
sandstones on the top of the Mountain Limestone, near 
Llanfair-dyffryn-clwyd for instance, and the sandstones referred 
by Mr. Maw, Geol. Mag., Vol. 2, (1865) pp. 380—524, to 
Permian, are, I think, certainly Carboniferous beds above 
the Mountain Limestone, as suggested by Mr. D. C. Davigs, 
Geol. Mag., Vol. 2 (1865), p. 478. 
Mr. CorRNWALLIS WEST took me to see the pits dug by 
Mr. Epwarps, and I found in the rock thrown out several 
plant remains, which were all undoubtedly Carboniferous. 
More clearly still, the beds which crop out in the bank of the 
Elwy, S. of Pontyralltgoch, must be referred to the Carboni- 
ferous. The bright red stain in some of the sandy shale, close 
to the bridge, induced a speculative miner to sink a shaft close 
to the bridge, and in the bed which was touched near the 
bottom of the shaft, about 15ft. from the surface, I found some 
small fragments of plants, one of which has been referred by 
Mr. CARRUTHERS to Sphenophyllum schlotheimi Brong. (See 
Schimper’s Paléontologie Végétale, p. 339.) The rest are 
parts of stems and bits of what look like Stigmaria rootlets. 
The specimens are all in-the Museum of the Chester Nat. 
Sci. Soc, 
This discovery I was unfortunately unable to follow up, as the 
whole thing fell in immediately afterwards, burying the windlass 
and other tackle at the bottom. But it is quite enough to con- 
firm the suspicion arrived at from the lithological character of 
the rocks, that the boundary of the New Red must be carried 
forward at any rate to the river under Maeselwy. 
