386 FOSSIL FISH. 



lake of Lucerne, and extends from north to south almost into 

 the canton of Berne. On the most elevated point of the moun- 

 tain, and somewhat below it, a considerable quantity of 

 ichthyolites are found in the slate rocks, which detach easily by 

 foliation. In almost all of them a fish may be found. The 

 projecting part is reduced to dust, but the impression is left. 

 A great quantity of teeth are also found here. It appears that 

 Mount Pilate is not at all of the same nature as the strata of 

 Glaris, as to geological structure. 



It is especially in the county of Mansfeld, in Thuringia, 

 Voigtland, and the Palatinate, that the most remarkable 

 depots of a species of ichthyolite are found inclosed in the 

 metalliferous slate. The places where they are more particu- 

 larly found are : — In the territory of Hesse, Riegelsdorf, 

 Thaliter, &c, ; in the Mansfeld county, Rothembourg on 

 the Saale ; in Thuringia, Eisleben, Sondershausen, Sangers- 

 hausen, Kamsdorf, Bottendorf, Saalfeld, Ilmenau, &c. ; near 

 Magdebourg, Alvensleben ; in the Palatinate, Munster-Appel, 

 and the environs of Kreuznach. They are also found in 

 France, near Autun, in the department of the Haute-Saone, 

 three leagues from that city, in a mountain called La Muse. 



It appears that the substance of their flesh has penetrated 

 the stone, which replaces it, and has modified the latter. 



In some cases, the impression of the fish scarcely occupies 

 any thickness. It is represented by scales, fins, and the head, 

 all flatted. The stones, containing these fish, are divided into 

 two parts, so that this image is found on each of the two 

 pieces. 



These fishes, which may have been about three feet in 

 length, are for the most part on the back, or in violent and 

 bent positions, and the head is usually disfigured. The sub- 

 stance in which they are found, according to the agreement of 

 all mineralogists, is a coppery, marly, bituminous schist, 

 sprinkled with argentiferous pyrites, and sometimes with mer- 

 cury in the state of cinnabar. These schists must be very 



