210 NORTH STAFFORDSHIRE COAL FOSSILS. 



to science, and also many rare species, have been found 

 since the publication of Agassiz's work. Although perfect 

 specimens are not uncommon, by far the largest number 

 occur in a fragmentary condition, which renders the deter- 

 mination of their specific peculiarities a task of some 

 difficulty. Enough, however, is left to enable us to learn 

 much of the structure of the ancient Carboniferous fishes. 

 In several of the ironstone shales, particularly that of the 

 Deep mine and Knowles, they frequently occur in a fine 

 state of preservation. These fishes must have died upon 

 the spot where their remains are now found, and before 

 putrefaction commenced have been buried in the mud or 

 sediment now converted into shale. The fragmentary ones 

 could not have been so rapidly buried, but after death 

 were exposed to the action of the water, which scattered 

 their remains. It may be, too, that after death they were 

 subjected to the ravages of the numerous Crustacea which 

 abounded in the waters of that period, and which no 

 doubt acted as scavengers in keeping in check the accumu- 

 lation of decayed animal and vegetable matter : they 

 would devour the softer portions, and leave the bones and 

 scales to be scattered about. The fish remains are not 

 confined to the shales, but are frequently found in the 

 ironstones, especially in those of a nodular character. 



In the New ironstone measures there is a remarkable 

 bone-bed varying in thickness from half an inch to two 

 inches or more. This bed is entirely made up of fish 

 remains, broken fin-spines, teeth, coprolites, scales, and 

 other parts, which are indiscriminately mixed together. 

 It would appear that during the deposition of this bed, 

 the waters swarmed with animal life. After death, these 

 creatures could not have been rapidly entombed, but must 

 long have remained exposed. How or by what means they 



