154 Fossils. 



Granitell is also composed of two sub- 

 stances ; black schorl, and white felsper, 

 mixed with some of the green felspar. 

 The only difference then between the 

 granitelles and the ophite is, that the 

 schorl which enters into the composition 

 of the former is not of the same kind as 

 that in the latter. 



Granite is composed of felspar, schorl, 

 and quartz. The colour of granite is 

 various ; it is hard, difficult to be work- 

 ed, and receives a fine polish- 



Flint is a hard opaque stone, suscepti- 

 ble of a very beautiful polish. It appears 

 to be composed of concentric strata, and 

 has considerable brilliancy on its frac- 

 ture. Flints are never found in continued 

 quarries, like the other stones ; they are 

 found detached, and dispersed through- 

 out the fields. When joined by any 

 kind of cement they form pudding-stones. 

 They become decomposed in the air, for 

 they are found for the most part covered 

 with a crust, of a softer nature than the 

 interior part. Their colour is exceeding- 

 ly various ; some of them are spotted and 

 yariegated with veins, others exhibits 

 the resemblance of plumes, and even of 

 plants. 



