In Carboniferous and Permian Epochs 149 



are of a dark grey to brown color, are of a fine close grain, 

 they split into layers or sheets, and the strata are 5 to 6 

 feet thick. But the bands form only a thin part of the 

 shales arid sandstolnes in which they He. These have 

 been grouped as follows by Lambe (p. 11) : 



Calcareo-bituminous shales, from grey to dark brown in color, 



including the so-called Albert shales 850 feet 



Grey bituminous and micaceous oil-bearing sandstone, and lower 

 conglomerates, in massive beds, usually of reddist tint, and 

 unconformable to the preceding 700 feet 



Following R. D. Stewart he inclined to view the bitumin- 

 ous material largely as a product of plant decomposition. 

 He also regarded the fishes as being marine, for he ob- 

 serves: "It is probable that the waters in which lived the 

 fishes about to be described, were cut off to a great extent 

 from the sea, and formed the lagoons in which the material 

 that produced the shales was deposited." And as to the 

 quantity of these fishes he adds: "the numberless remains of 

 fishes In some of the beds can be attributed only to the 

 occasional wholesale destruction of the fishes." But the 

 associated plants, the correlated resemblance in details to 

 the Scottish beds, the complete absence of true marine 

 remains, and the undoubted freshwater habitat in other 

 regions of the genera he treats of, clearly prove the beds 

 to be freshwater deposits. In this, as in many other cases 

 now cited, we would trace the origin of the bituminous 

 supplies to chemical or biochemical decomposition of the 

 oils contained in the fishes. 



Of the fishes that he describes he remarks regarding 

 Rhadinichthys alberti that It" evidently swarmed In count- 

 less numbers In the waters of its time." Scarcely less 

 abundant was Elonichthys browni, the general aspect of 

 which, as well as the structure of the ganoid scales from 

 different parts of the body are shown In Fig. i8. 



In the eastern and central States, conditions closely 

 simulating those already given, prevailed during deposition 

 of the middle and upper Misslsslppian. But such often 

 alternated with invasions of the sea, and so of a marine 

 fauna. This is well set forth In the elaborate reports of 



