Trof. T. Rii])ert Jones — Address. 569 



Giimbel and Geinitz have described them as belonging to Unio and Anodott ; and 

 Ludwig refers Anthracoptera to Breissma. At all events there is a great probability 

 of their not being truly marine. They may have lived in the brackish water of 

 lagoons and creeks in the black, muddy swamps, having some commnnication with 

 the sea, and often or occasionally inundated with salt water (Dawson, Salter, etc.). 



Spirorbis carbonarius is frequent in the Coal-measures of South Wales and else- 

 where. This little annelid, though belonging to a marine genus, is often found 

 attached to plant fragments in the coal-shales. These plants may have hung down 

 into the water and been infested by the annelid ; or it may have attached itself to 

 floating plants which were ultimately drifted back to the littoral mud-swamp. This 

 iSpirorbis is an important constituent in the Ardwick limestone of Manchester and 

 Shropshire, but is associated with Ostracoda {Carbonia), which are probably of 

 brackish -water habitat. 



The Brachiopoda are necessarily marine. The fish are not good witnesses, for 

 they might have migrated to and fro, as some now inhabit both fresh and salt 

 waters ; and some might have been essentially estuarine. 



Thus there are few decidedly marine beds in this series, and these, of course, 

 correspond with the occasional domination of the sea during its inroads and during 

 extreme depressions of the district. 



In addition to the occurrences of fossils in Salter's list above quoted we may 

 notice that in the Geol. Mag. 1870, pp. 214-'2'20, is an account of some fossils 

 discovered by the late Mr. W. Adams, of Cardiff, in 1869, in a 'Black Band' in 

 the Khymney Valley, about 800 feet higher in the Coal-measures of South Wales 

 than any hitherto found. The band is calculated to have been rightly 81 feet above 

 the Mynyddyslhvyn coal, from which it is divided by a fault ; it is in five layers and 

 about 8 feet thick, with its associated shales. One of these in its midst and the 

 lowest shale carry the fossils. With some plant remains there is Anthraconif/a, with 

 Estheria (?) Adamsii, E. tenella, and Lt-ala Leidi/i, all probably of brackish 

 habitats ; also Caibonia Evelinm and C. Agues, Ostracodes typical of a genus which 

 is found in the black shales, presumably of either fresh or brackish- water origin. 

 Mr. Adams also found a shale full of Amhracomya at Aberbeeg, Ebbw Vale, over- 

 lying the Troed-rhiw-Clawdd coal, and 226 yards below the Mynyddysllwyn coal 

 (p. 215). 



2. Of the Vertebrata the fishes enumerated in Mr. Salter's list are important. 

 The following are the genera named: — Megalichthys, flhizodus, Pleuracanthus, 

 Byssacanthus i?), Palseoniscus, Amblypterus, Helodus, and Poecilodus. 



Although reptilian remains are rare in South Wales, yet they are not altogether 

 wanting. In 1S65 ^ Professor (now Sir Eichard) Owen described some remains of a 

 small amphibian (between newt and lizard), found by the late J. E. Lee in the lower 

 part of the Middle (or upper part of the Lower) Coal-meaures at Llantrissant, 

 Glamorganshii'e. The animal was rather larger than the allied Dendierpeion 

 Acadiaiiuin, and Professor Owen named it Anihrakerpeton oassosttum, "the thick- 

 boned coal-reptile." This paper and its illustrations were reproduced in the " Trans. 

 Cardiff Nat. Soc." 



10. Extent of the Coal-measures under the South of England. — Sir H. De la 

 Beche in 1846 ^ noted that a great sheet of Palaeozoic rocks, including the Coal- 

 measures, extending from Belgium to Central England, had been rolled about, 

 ui;dulated, crumbled, and then partially worn away before the New Eed Sandstone 

 and other Mesozoic strata were laid down upon them ; and that these, in their turn, 

 had been denuded so as to expose here and there portions of the underlying Coal- 

 measures, though near by a ridge of profitless Mountain-limestone or other older 

 rock might come to the surface. 



In 1856 Mr. Godwin-Austen, following up his reasoning about the areas of coal- 

 growth (see above, page 521), explained that the movements of disturbance which 

 they had undergone had tended to preserve the great Franco -Belgian coal-band, and 

 had rendered it available ; and he proceeded to state that the course of that band of 

 Coal-measures may be traceable westward, and probably coincided with, and may 

 some day be reached along the line of, the Valley of the Thames. 



Professor Prestwich in 1871 extended this inquiry;^ and, having carefully com- 



1 Geol. Mag. Vol. II. pp. 6, 8, Plates I. and II. 



2 Mem. Geol. Surv., vol. i. pp. 213-214. 



^ Report Royal Commission Coal-Supply, 1871 ; Anniv. Address Geol. Soc, 



