TALCOSE SCHIST. 293 



TALCOSE SCHIST. 



THIS rock is now for the first time introduced 

 into a geological arrangement, though it is often 

 mentioned by writers, and frequently found in 

 the cabinets of collectors, 



Although it is not common, and, where it is 

 found, is also very limited in extent when compared 

 with the other primary strata, it seemed impos- 

 sible to avoid giving it a place here ; as it occurs 

 in the form of a rocky stratum in alternation with 

 other substances, and cannot be considered as a 

 variety of chlorite or of micaceous schist, when 

 the three minerals which give the character to 

 these compounds, are considered distinct 



As the space which it occupies is commonly 

 very small, the strata are neither very thick nor 

 persistent : and, in some cases indeed, it occurs 

 in such minute quantities, that, were there no 

 examples of its existence in larger masses, it 

 might without inconvenience have been omitted 



