76 T. STERRY HUNT: SUPPLEMENT TO 
the nature of which has been shown;..... thus constituting a veritable passage in time 
from the granitoid gneiss at the base of the Laurentian, through the intermediate Huro- 
nian and Montalban divisions, to the less markedly crystalline schists of the Taconian.”’ 
While rejecting, in these terms, the notion of the common palæozoic age of the various 
and dissimilar groups of crystalline stratified rocks in north-eastern America, still main- 
tained by some partisans of the Huttonian dogma (one of whom speaks of them as repre- 
senting “ grades in metamorphism”), it must not be forgotten that the genesis, by differ- 
ent chemical processes, of certain silicates has been continued under various conditions, 
through paleeozoic and more recent times to our own. This is seen, not only in the gene- 
ration of pectolitic and zeolitic silicates in the channels of thermal springs, in the deep-sea 
ooze, and in basic eruptive rocks of later as well as earlier periods, but in the zeolitoid sili- 
cates, like hamelite, which I have described as injecting paleeozoic crinoids and mollusks ; 
SUB-ORDER II.— PROTOPERSILICATE. 








een ee sr = 
. |6. Zrozrrorn. |7. PROTOPERSPATHOID. 8. PROTOPERADAMANTOID. 9. PROTOPERPHYLLOID. 
WM 2 272 2 Sie 
V=7°2—6°3 V = 8°6 — G°1 V=—5°8—4°7 V = 62 —5°1 
| 
XZ: 4:m |- - - - = | Melilite. Eudialyte. - | Pargasite. Keilhauite. - - - - - - Phlogopite. = % 
| : & | A large group of 
SS es) aR - - - | Wôhlerite. Ilvaite. - | Idocrase. Schorlomite (#:3). - - - Phlogopite. - = 4 hydrous magne- 
= a a a es A 
1: 1 :m | Xanthorthite. re CRM ent Garnet. Ægirite, Allanite. Beryl. - Bottes ne ele me aa ae 
say san j= = = = - | Barylite. <= - = - Euclase. Ardennite. Prehnite. - Seybertite. 10. Prsrrorp. 
2 = Hamelite. À = : : Axinite. Epidote. Zoisite. Jadeite. 2 x Fey. 
Na gen À Catapleiite. $ Scapolites. Sodalites. I} Gastaldite. Acmite. - - - - - | ; | Willcoxite. - Jollyte 
6 A Fahlunite. 
LS: ||| ZEOLITES. | PELDSPATHIDES=) NES CCC Coronite.  ) Zinnwaldite. } Brnraisibes 
a 
= i. Edingtonite. : 2 §Spodumene.Sapphirine.? | : Aohte me ilite (L : 5). 
i:4:n } Sloanites i Petalite. - - S =| senate Sa © oi Schorlite. Lepidolite Hygrophilite ( ) 
: ra Margarite- ; 
1:16) mach orestitie. Ne TS ESS ia = PERS) RE ESA EE NER teres j Moscovite: Sordavalite. 
U i 
Beste eran || Ses ks. om al lla eye | nea eae <Aphunite: Euphyllite. |Pinite. 
ij 
= ‘ 3 
Bush stan” [Seg Serer ele TUE S|= 32 = = ==) =| Indicolite: nes Cossaite. 
Mis PS NN CS ROC RCE Rubellite. Muscovite. | (Palagonite. 
Tachylite. 
(With other Pitchstone. 
species). Obsidian.) 


in the glauconite and related species formed from the Cambrian period down to the present 
day ; in the deposition of serpentine in Silurian strata; and in the sepiolite beds of the ter- 
tiary period—the results of processes in which solutions like those which have given rise 
to the crystalline pectolitoids and zeolitoids are supposed to have intervened ” 
§ 16. Neither is the fact to be overlooked that local changes, probably through the 
intervention of thermal waters, and sometimes, though not always, visibly connected 
with the intrusion of plutonic rocks, have (as first pointed by me in 1869 *) effected alike 


1 Hunts Azoic Rocks, p. 253. 
? See on the Serpentines of Syracuse, New York, Trans. Roy. Soc. Can., Vol. i. Sec. iii. §§ 27-35; also the 
Genetic History of Crystalline Rocks, [bid., Vol. iv. Sec. iii. §§ 1-13. 
’The Chemistry of the Earth; Report of Smithsonian Institution, 1869. Also Chem. and Geol. Essays, p. 306, 
and the Origin of Crystalline Rocks, Trans. Roy. Soc. Can., Vol. ii. Sec. iii. §§ 114-116. 
