294? GENERAL COMPARISON OF 



The rocks which follow, consist of the most remarkable 

 varieties of Chlorite schist. 



1 . Chlorite schist, formed of simple undulated, or straight 

 scaly chlorite. 



2. Schistose chlorite with quartz, sometimes finely lami- 

 nar, sometimes granularly laminar, occasionally so compact 

 as to be scarcely fissile. 



3. Chlorite schist and felspar, either scaly or fibrous in 

 the fracture, and schistose. 



4. The same, except that the felspar is arenaceous, and 

 scarcely distinguishable from quartz, without trial of its 

 hardness, or observations on the effects of the weather 

 upon it. 



5. The same, containing in addition, distinctly imbedded 

 crystals of common felspar. Similar felspar crystals are 

 also found imbedded at times in common schistose chlorite. 



6. Chlorite schist containing crystals or scales of black 

 mica. 



7. Chlorite schist and hornblende in a state of intimate 

 admixture, the structure intermediate between scaly and 

 fibrous. 



8. Chlorite schist and aetinolite. 



9. Simple chlorite schist containing distinct crystals 

 of hornblende. 



In all these cases, additional variations take place from 

 the occasional verging of the schistose chlorite to talc or 

 to mica, from neither of which indeed is it at times easily 

 distinguished. 



The following are triple and quadruple compounds, and 

 must for the present be ranked either with the varieties 



chlorite with hornblende, with mica, with quartz, with felspar, or with 

 more than one, or even two, of these ingredients. Still, in a geological 

 sense, these several mixtures are received as varieties of one leading 

 rock ; and it is only in this sense that the privilege is claimed of apply- 

 ing the general term hornblende schist to the several varieties here 

 described. 



