508 
THE GEOLOGIST. 
hisulcatus. Next in successive order is the "Blue Vein" ironstone, which 
abounds in Anihracosia aquilinus and Spirorlis carhonarius, and much 
more rarely, a species of Mbdiolopm. Above this is the "Red Vein " 
ironstone, from which I have obtained Cardiomorplia. Then comes a 
coal-bed, about four or five feet thick, known in the north-east crop as 
the " Old Coal," and about Merthyr as the " Lower Pour-foot Coal," in 
the shale of which two species of Unio occur, together with a small 
Modiola. In the rock below this coal at Beaufort I have observed 
well-marked traces of a small crustacean. Many such traits, I have no 
doubt, would come to light by careful search, for there must have been 
an enormous amount of surface exposed in the wet sands and mud of 
that age, although at present we know but little of their remains. Above 
the Old Coal are two or three seams in which no fossil remains have 
been noticed, with the exception of one or two ferns and Lepidodendra ; 
but shells again appear in the shale of the " Dawen Pins," in 
the shape of JJnio centralis, which is very abundant, and Myalina quad- 
rata, which is more scarce. Above this is the " Bydellog Coal," an 
important seam, running through the greater part of the district, and 
averaging from five to ten feet in thickness. At Ebbw Vale one shell 
has been procured from this coal, an Athjris planosuleata, while in the 
shale of the equivalent coal at Pontypool, called there the " Meadow 
Vein," Prodiwtus scabrimlus is common, the only Productus known in 
the true coal-measures. Above the " Bydellog" is the " Three-quarter 
Coal," which has yielded (although I cannot vouch for the accuracy of 
the locality) a Terelratula hastata. It was found in the rubbish -ground 
of this coal by Mr. Adams, of Ebbw Vale, but he was not absolutely 
certain that no shales from another coal might not have been acci- 
dentally mixed with it. This is, at all events, a mountain-limestone 
shell from the true coal-measures, and if it be from the " Three-quarter 
Coal," it is the highest range of the species in the coal-basin, being be- 
tween six and seven hundred feet above the mountain-limestone. A seam 
of coal immediately above this, the EUed, has given us no shells, but an 
amazing quantity of ferns in beautiful preservation, of which I possess 
more than forty species ; but, as they are foreign to the present subject, 
I will not now enumerate the list. 
A small vein of ironstone, the " Black Pins," lies about ninety feet 
above the Elled, in which Unio aquilinus is tolerably common. In the 
" Soap Vein " of coal, a small seam higher still, a shell, probably Unio, 
