HORNBLENDE SCHIST. 303 



Hornblende schist is far less commonly asso- 

 ciated with micaceous schist, but is also found 

 in that situation, forming occasional beds of very 

 various dimensions. In these instances also, it 

 sometimes passes into the micaceous schist by 

 means of those varieties of the latter rock already 

 mentioned under that head. Such intermediate 

 substances are, as in most other cases, noted in 

 the synopsis under each title, that the student 

 may be at no loss in referring to them. 



In almost all cases where hornblende schist 

 occurs in the situation last mentioned, it is ac- 

 companied by chlorite schist, and by many ano- 

 malous compounds, which will be found enume- 

 rated in the synopsis^ under the general title of 

 those rocks to which they seem most nearly 

 allied. But, besides this, it is found, in Scotland, 

 forming a member of a very extensive and singu- 

 lar association of strata, already noticed under 

 the head of chlorite schist, and consisting prin- 

 cipally, or essentially, of quartz rock, micaceous 

 schist, chlorite schist, and hornblende schist. 



This rock is not often found associated with 

 argillaceous schist ; but where this occurrence 



