540 PAL^ONTOLOGICAL REPORT OP GEOLOGICAL SURVEY. 



Coal No. 9. This is, in western Kentucky, a reliable bed, and its 

 coal is generally of very good quality. It is so well characterized by 

 the fossil remains of its shales, that it is easily identified. Its thick- 

 ness varies from three to five feet, and it is covered with a thick bed 

 of black, hard, laminated and slaby shales, which contains a quantity 

 of vegetable, but especially of animal, remains. The plants preserved 

 in the shales are mostly stems of ferns, and pieces of the bark of 

 S'igillaria. The shells, much more numerous, at least as individuals, 

 have two species, which may be taken, among others, as characteristic, 

 viz: Avicida redalateraria and Produclus muricatus. Teeth, scales, 

 and fins of fishes, (Icythyodorulites) are also found in the shales of 

 this coal, with the shells, but those remains are in great' abundance only 

 where the shells have disappeared; we have found them in all the 

 places where we had an opportunity for the examination of the vein, 

 ordinarily accompanied by a conical, regularly-ribbed print, about half 

 an inch deep, and nearly as broad at its base. This fossil has been re- 

 ferred to a peculiar scale, which covers the head of a kind of fish, 

 Cephalapsis, of which the caudal square and shining scales, are also 

 found on the same shells with remains of small Pterichthys, another spe- 

 cies of fishes of the Coal Measures* Sometimes, also, these remains 

 were accompanied with well marked small Calamites, which, from their 

 length and their slenderness, appear to have lived in deep water. 



The remains of fishes which abound in the shales of coal No. 9 are 

 also found, apparently of the same species in the shales of coal No. 11. 

 In this way, if the identification of both these veins should repose on 

 palaeontology alone, it would be sometimes impossible to make a dis- 

 tinction between them, except by means of the shells, which, however, 

 are not found everywhere. The shells themselves are numerous, and 

 of species so very like that it requires a good deal of scientific perspicaci- 

 ty to distinguish them. But the identification, or rather the distinc- 

 tion of the beds is easily made out from this difference, that No. 11 

 coal is ordinarily separated into two by a clay parting, and that its 

 shales are covered by limestone, either as a more or less well developed 

 continuous or interrupted limestone, or indicated by a ferruginous clay, 

 containing the shells of this limestone. Moreover, the shales of No. 



* Ly ell's Manual of Ocologjr, p. 344, 346. 



