296 TALCOSE SCHIST. 



of structure requiring notice; and, as far as I 

 have observed, it does not occur in a contorted 

 state, like micaceous schist ; although it is some- 

 times minutely undulated. 



Its mineral composition resembles that of the 

 two preceding rocks, as it may consist either of 

 talc alone, or of talc and quartz, together with 

 some less essential minerals. It is always suffi- 

 ciently distinguishable from those rocks by the 

 peculiar characters of the talc, and its colours are 

 generally limited to white, lead grey, and dark 

 obscure green. 



SYNOPSIS OF TALCOSE SCHIST. 



FIRST DIVISION. 



Simple : of one ingredient, 



A. Schistose/talc, 



a. Scaly- and foliated. 



b. Scaly and semigranular. 



c. Minutely scaly-granular and indurated : the 



potstone of some mineralogists. 



