A NATURAL SYSTEM IN MINERALOGY. 73 
graphic mineralogists have assigned to crystalline individualization, which is but an 
accident of certain mineral species, a disproportionate importance, and a significance 
which has often been misleading. Systematic mineralogy includes all inorganic matters, 
whether gases, liquids or solids, and these latter, whether individualized as crystals or 
existing in the colloidal or porodic state. 
§ 14. The genesis of the various mineral species of the earth’s crust has been effected 
by continuous dynamic and chemic agencies working through successive ages, and has 
determined the differences met with in the successive groups of neptunian rocks, with their 
gradations in character, from the ante-gneissic granite down to the youngest crystalline 
schists and the detrital sediments of still later ages. The same is true of the plutonic 
rocks of different periods, and the laws which have regulated this terrestrial process are, 
as we have elsewhere endeavoured to show, not less certain and definite than those of 
SuB-ORDER I. — PROTOSILICATE. 

== E 

ea 1. Pecrozrroip. 2. PROTOSPATHOID. 3. PROTADAMANTOID. 5. Opurrorp. 
mee V=7°0—5°3 V=6'7—6'0 V=6-0—4°6 V=7°3—5°5 
= re al à ae : =! 
Bsa a R= a) ES Danalite (7:6). - - - - - - - | Chondrodite. 
|§ Willemite. Knebelite. Batrachite. ? | § Monticellite. Chrysolite. 
1: 1 | Calamine. Thorite. Cerite. - |} Tephroite. Gadolinite. Helvite. »|? Phenacite. Bertrandite. 


1:1} | Chrysotile. - - - - - - Leucophanite. - - - - - - D SES ER CN EE © Serpentine. Retinalite. 
1:1} | Gece: Gee s À CRE eh ommae ARR Re metas Deweylite. Genthite. 
1:2 Mn er eu } | Wollastonite. Tscheffkinite. - - - | } raphe BRAS i SE LE 
1:22 | Pectolite. - - - - - - - TS ne DAMON HOT Amphibole. - - = - - - Spadaite. 
LACS EE EN Eee Sy SC LR eee MN) Sei SE CN CANIS CEE Rensselaerite. 
TOI ace oor one ie ENS. Seaton Schott ee 1 - - - - - | Sepiolite. Glauconite. 

1:3} | Datolite. 4, PROTOPHYLLOID. 
A: 4 | Apophyllite. Okenite = -|- - - - - - - - - - - - - - | Guarinite. Titanite. —_ 
F Thermophyllite (3 :4). 
Lb BCE eye SS 3 En Cl NES Palen SG Sen: RS ts Danburite. TE (2 . 5). 
Tale (2 : 6). 





astronomical and of biological evolution. The changes seen in comparing alike the 
neptunian and the plutonic rocks of succeeding geological periods, mark the steps in the 
mineralogical evolution of the primeval globe. The differentiation of the first anhydrous 
mass through crystallization and eliquation, the subsequent intervention of permeating 
waters, the continuous processes of solution, deposition and segregation, the intervention 
of atmospheric decay, and of the products of subaerial action, alike upon plutonic and 
crenitic rocks, and upon the ocean’s waters, are all factors in this great mineralogical 
evolution. 
§ 15. The mineralogical differences in the various groups of neptunian rocks, as I 
wrote in 1878, “are not the result of subsequent and unlike changes which one and the 
same uncrystalline paleeozoic series has suffered in different geographical areas, but on 
the contrary belong to successive periods in palzeozoic or eozoic times. The great divisions 
of the latter... .. present, in ascending order, a progressive change in mineral characters, 
