344 REPORT — 18G4. 



and upwards, varying m species and thickness of deposit, occasionally form- 

 ing compact masses several feet in depth, and affording, independent of their 

 geological interest, in many well-known cases a reliable key to the miner in 

 his critical and laborious pursuits. 



The distribution of fish-remains is as a rule more general and uniform than 

 that of the mollusks ; and although in the presumed marine deposits there 

 is a specific difference in the case of Palceoniscus, in no other genus met with 

 is it perceptible. In the haematite bed a fish-scale, and one only, has been 

 found, and this, the earliest representative of the order appears to be an ex- 

 ample of DipJopterus. The Stinking-Coal shales contain, intermixed with the 

 marine fossils enumerated, two or three species of Palceoniscus, large spines, 

 and a curious palate as yet undescribed ; and it is an interesting fact in con- 

 nexion with this bed that in no other deposit but the shales of the Bay Coal 

 have simdar species of Palceoniscus been met with. As far therefore as the 

 subject has been investigated, two instances occur throughout this enormous 

 deposit of coal-measures, of the introduction on a definite horizon of animal 

 life restricted to jjarticular limits, and holding no communion with that by 

 which it was preceded and followed, 



Palceoniscus is the most widely distributed fish in this field, remains of it 

 being found in nearly sixty different beds ; it often occurs in a beautiful 

 state of preservation, especially in the shales of the Deep Mine ironstone at 

 Longton ; and it may be here remarked as a somewhat significant circum- 

 stance that, in coal and ironstone shales thickly charged with shells, fish- 

 remains seldom occur otherwise than as detached scales and teeth ; and even 

 these as a rule are confined to a bed, lying in the form of a bone-bed, imme- 

 diately upon the coal or ironstone with which they are associated. The 

 ironstones of the Knowles and Cockshead coal often contain weU-preserved 

 fish ; and in the shales of the former, as well as in those of the Brown Mine, are 

 occasionally found concretionary masses of shells in the form of nodules, but 

 in no instance has either fish or sheU been detected within the body of coal 

 itself, although almost every coal-seam contains upon its upper surface a 

 thin coating as it were of broken and detached organisms, either fish or shell, 

 or both. It would therefore appear that after the submergence of the coal- 

 bed, and before the waters had become charged with mud or other extra- 

 neous matter, subsequently deposited, the fish or moUusk sinking to the 

 bottom was subjected to the action of currents, by which the disintegrated 

 parts were carried here and there, and redeposited on the surface of the future 

 coal-seam, or baud of ironstone. 



Succeeding Palceoniscus in j^oint of numbers and general distribution is a 

 fish with small cycloid scales, provisionally assigned to the genus Rhizodiis, 

 but to which in point of fact no satisfactory position has at present been 

 attributed. There are at least three speceies of it, and. Like Megalichthys, it 

 occurs in from forty to fifty separate deposits. Occasionally in the Brown 

 Mine, New and Knowles ironstones, are found portions of jaws of various 

 sizes, some of which belong undoubtedly to Megaliclithys, but others are as 

 yet undetermined. It is a circumstance of note, that of the great number of 

 such fragments of MegalicJithys as show scales in situ, not one has been met 

 with which could possibly have formed part of a fish less than 18 inches in 

 length, whereas in the case of the cycloidal-scaled fishes the majority of spe- 

 cimens range in length from 6 to 8 inches. With the other fish contained 

 in this field the Report will deal hereafter : as far as can at present be 

 ascertained, they comprise a list of nearly forty genera, represented by pro- 

 bably ninety species, many of which are new to science. 



