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arenaceous texture of the quartzose lamina in 

 this, generally presents a perfect distinction, in- 

 dependently of the geological position. As mi- 

 caceous schist often passes into quartz rock, it is 

 particularly indefinite with regard to that sub- 

 stance. The other cases in which it may lose its 

 distinct characters will be found in the twelfth 

 chapter. 



CHLORITE SCHIST. 



The presence of chlorite, or, to a beginner, 

 the green colour of that which would otherwise 

 pass for mica, is sufficient to distinguish this rock, 

 which, however, passes by an apparently indefi- 

 nite transition, into micaceous schist, and into 

 other rocks, as already noticed. 



TALCOSE SCHIST. 



This, rare rock, is also distinguishable by the 

 known properties of the mineral whence it de- 

 rives its name. Like the former, its analogy to 

 micaceous schist in the other general characters, 

 is perfect. 



