245 



on one side, leaving its impression on the opposite ; the other is, that 

 that the bony parts of the fish are changed into silicious matter *. 



At Gijon, in Naples, fish are found in a black fissile stone, and 

 mostly in a good state of conservation. But the black schist, in which 

 these remains are found in the greatest number and in the best state of 

 preservation, is in the neighbourhood of Eisleben, in the county of 

 Mansfeld, in Upper Saxony. This schist, which is argillaceous, is very 

 hard and black, and lays over coal. The fish are in various states, some 

 laying straight, others bent ; but all of them evidently much compressed. 

 The whole surface of the impression is as if varnished, or, according to 

 Mylius, as if covered with naphtha ; and many of the scales are entirely 

 resplendent and variously coloured, from their having become pyritous; 

 from which circumstance, these specimens often possess a very beautiful 

 appearance. In a specimen of this kind, from the Leverian Museum, 

 almost all the scales on one side are in a pyritous state, and the opposite 

 part of the schist, bearing the exact form of the fish, is covered with a fine 

 grey pyritous film. 



Mr. Knorr observes, that in general we may be able to determine the 

 situation in which these fossils were placed in the quarry ; since, on split- 

 ting the stone, the fish is most commonly adherent to the upper plate ; 

 whilst, on the lower plate, the impression only exists. M. Kruger is of 

 opinion, that the scales do not exist in these specimens; but, that the 

 lozenge-formed markings are the remains of the flesh. A white line 

 or pellicle, he observes, may be perceived to surround the fish, if the 

 stone is broken across ; and, in this part, he believes the scales to have 

 existed. 



The fossil fish of Pappenheim and of Oeningen, near the lake of Con- 

 stance, are found in considerable numbers, and in good preservation. 

 The stratification of the quarry in which they are found is, according to 

 the celebrated Saussure, 1. one inch of a grey, loose, fine-grained 'sand- 



Voyages Physiques, &c. par Scipion Breislak, p. 20. 



