Geology of Coalhrook Dale. 443 



always confined to the size of the Conulariae, but are frequently larger, and when such specimens 

 can be separated from the matrix, they are generally found to consist of an oval body, without any 

 traces of external markings, the larger axis being traversed by a Conularia, the apex of which some- 

 times slightly protrudes. Whether this body be part of the Conularia, I cannot decide ; but its black 

 colour indicates animal matter. Another characteristic fossil of the Penneystone measure is the 

 Orbicula reflexa, of which several specimens are frequently found in one nodule. The exterior of 

 the shell, which is either black or speckled white and brown, generally retains its beautiful lustre, 

 but the organic matter is almost entirely replaced by the substance of the matrix — except in a very 

 few instances, where a fine white, very delicately striated shell remains. Several species of Unio, 

 often of a large size, occur in the measure. The Bellerophon is rare, except at Langley, where 

 some of the large thin flakes of the ironstone are full of them. Nautili are common ; but 

 univalves are rare, (see Appendix, list of organic remains). Mr. Anstice has lately obtained 

 portions of a column of Cyathocrinites quinquangularis in a Penneystone nodule at Madeley. 

 The fragments in the centre of the nodule consist entirely of the substance of the matrix ; but 

 although no organic matter remains, the surface of the encrinal column and its plates exhibit 

 a vitreous lustre similar to that of the facets of crystals, and like them, separating easily in the 

 direction of the natural surfaces. When the fossil occurs upon the outside of the stone, no such 

 appearance is exhibited. At the Horsehay pits, I have since found numerous specimens of the 

 same Cyathocrinites ; but in this case, the organic matter is replaced by light yellow, earthy car- 

 bonate of iron. The presence of sauroid fishes in this deposit is of considerable interest. The 

 remains of these animals have been long noticed in the coal-measures, but it is to the recent 

 labours of Dr. Hibbert-Ware* and M. Agassiz t that we are indebted for the determination of 

 their nature. 



In the first volume of the Zoological Journal, Mr. Sovverby figured and briefly described the 

 ray of the Gyracanthus formosus ; but he confessed that he was unable to refer it to any known 

 genus. This specimen was from the Newcastle coal-field ; and in the Museum of that town, Mr. 

 Hutton showed me several similar rays. Mr. Anstice has had fossils of the same nature in his col- 

 lection for many years. Dr. Hibbert-Ware in his able memoir says, " the limestone of Burdiehouse 

 entombs thorny vays of immense magnitude, and most beautifully configurated, wliich it is im- 

 possible to contemplate without amazement. M. Agassiz proposes to name the fish to which 

 these rays belong, the Gyracanthus formosus." In the shale of the Penneystone, but also upon the 

 exterior of the ironstone nodules, are occasionally found the angular scales of that remarkable 

 sauroid fish the Megalichlhys Hihherti. The scales differ slightly from those which I have seen at 

 Burdiehouse, their lustre externally being greater, and their colour much darker. Dr. Hibbert- 

 Ware states that " one description of scales (of the Megalichthys) exhibits a coating of enamel of a 

 nut-brown colour, and often of the most brilliant lustre imaginable. These scales are of various forms, 

 though generally angular. A most curious character is the punctured surface which many of 

 them display, a character which I have traced, though in a less prevalent degree, in the scales of 

 the recent crocodile." Some of the large plates of the head are found at Madeley in a perfect state, 

 and are mottled dark brownish grey, (see Plate XLI., fig. 10, 11.); the scales of the body are 

 rarely in position, but I have met with one specimen in which several of them were continuous. 

 This specimen also exhibits a few of the vertebrae, which are about three-quarters of an inch in 

 diameter, and concave on both sides ; the last-mentioned remains are very scarce %• 



* Trans. Royal Society of Edinburgh, vol. XIII. t Poisson's Fossiles, tome ii., p. 87. 



;{: Mr. Anstice's collection contains a beautiful series of the organic remains of this stratum. 

 VOL. V. SECOND SERIES. 3 M 



