508 THE GEOLOGIST. 



hisulcatus. Next in successive order is the ''Blue Vein" ironstone, which 

 abounds in Anthracosia aquiUnus and Spirorhis carlonarius, and much 

 more rarely, a species of 3fodiolopsis. Above this is the ''Eed Vein " 

 ironstone, from which I have obtained Cardiomorpha. 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 Unio centralis, which is very abundant, and Ilyalina 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 Athyris planosulcata, while in the 

 shale of the equivalent coal at Pontypool, called there the " Meadow 

 Vein," Froductus scabrioulus 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. Tt 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 furty 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 EUed, in which Unio aquiUnus is tolerably common. In the 

 " Soap Vein" of coal, a small seam higher still, a shell, probably Utiio, 



