245 
is, that the fish, on splitting the stone, is not divided, but remains on 
one side, leaving its impression on the opposite ; the other is, 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 lies over coal. The fish are in various 
states, some lying 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, bear- 
ing 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 splitting 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 
Constance, are found in considerable numbers, and in good preser- 
vation. The stratification of the quarry in which they are found is, 
according to the celebrated Saussure, 1. one inch of a grey, loose, 
* Voyages Physiques, &c. par Scipion Breislak, p. 20. 
