294 TALCOSE SCHIST 



in a classification of rocks, and enumerated as a 

 modification of the simple mineral, talc, whence 

 it derives its name and character. 



It is sometimes found to form thin beds in a 

 series of gneiss, in which case it is often asso- 

 ciated with the hornblende schist or actinolite 

 schist, which so often occur in the same situation ; 

 and it, commonly also, in these cases, is con- 

 spicuous on account of the imbedded extraneous 

 minerals, such as actinolite and cyanite, which it 

 contains. 



In a series of micaceous schist, it may also 

 sometimes be observed that a gradual change of 

 character takes place in some of the beds, and 

 that they ultimately pass into this rock ; which is 

 thus found occupying a certain limited space in 

 the series, very often presenting the form of an 

 imbedded and stratified mass ; since such collec- 

 tions of strata of talcose schist, are generally 

 thick in the middle, and gradually evanescent at 

 the edges. Sometimes the transition takes place 

 by the intervention of chlorite schist ; and talcose 

 schist is also, in a similar manner, sometimes 

 found imbedded in a series of this rock. 



