Liihological Nomenclature. 237 



<9r, again, 



Crystallites, 

 Clastites, 

 Aggregites, 

 Atnorphites. 



The term-! of the last named group may be defined as follows : 



Cri/stallit^s, those rocks that are crystalline in structure ; 



ClastUes, those which are fragmental or detrital in origin ; 



AryjregiteSy those which are simply accumulations of individ- 

 ualized panicles of matter, coherent or incoherent, neither crys- 

 talline nor detrital io origin, as infusorial earth, or chalk, when it 

 is composed of uncomminuted Ehizopod shells ; 



Ainorpldies, those rocks in which there are no discernible indi- 

 vidualized constituents. 



Class II. Basis of Glassificaiion. — Structure of the Mass. 



Schist, 

 Shale, 

 S a'e, etc. 



Or, again, 



Stratified, 

 Uustrdlified. 



Glass 111. Basis of Classification. — The Crystalline Character of the 



Constituents. 



Granite, (crystals distinct). 

 Granulite, (crystals minute). 

 Aphanite, (no visible crystals). 

 Porphyry, (crystals in compact base). 



It is proposed to restore the term granite to a proper etymo- 

 logical use, and apply it to rocks consisting of distinct, crystalline 

 grains of medium or large size, and to deprive it of mineralogical 

 signification, making it a term denoting simply a certain class of 

 cry- tai line aggregates. 



It is proposed to designate minutely granular crystalline rocks, 



