T. S. Hunt on Ophiolites. 217 
Arr. XX.— Contributions to the History of Ophiolites. Part I; by 
T. Srerry Hunt, of the Geological Survey of Canada. 
Iv the published reports of the Geological Survey of Canada, 
Sir W. HE. Logan has already shown that the id entines of 
the Green Mountains occur in the form of beds, and that they 
Occupy a constant position in the series of altered Lower Silu- 
nan strata which make up the principal part of the Green 
ountain chain. These metamorphic strata consist of feld- 
spathic, micaceous, epidotic, chloritic, taleose and argillaceous 
schists, with quartzites, limestones, dolomites and magnesites; 
1 P to the present time, geologists, with few exceptions, have 
cooked upon serpentine as a rock of igneous origin ; is 
oe to show, the result of the alteration of beds of silicious 
olomite and magnesite, which have been transformed into sili- 
whic a 
les us to explain the production of those silicates of lime, mag: 
ee and iron which play such an important part in the mineral 
tory of the crystalline stratified rocks.* 
se results of my examinations of some of the so-called serpen- 
herocks of the Green Mountains, The following pages are 
| 
9 
B 
fa) 
< 
ro) 
— 
g 
5 
® 
° 
ro) 
=} 
e. 
=] 
ta 
= 
f°) 
o 
wm 
=} 
ros 
78 
° 
= 
® 
oO 
5 
Ce 
e 
* 
3 
ie) 
a 
In 
ot 
a 
B 
ie) 
° 
| 
ct 
# 
Qu 
=a 
i} 
E 
o 
A 
B 
8 
B 
ot 
B 
QO 
3 
» &te., are repeated with certain differences, offering an in- 
oldest known sedimentary rocks were similar to those which 
Prevailed during a portion of the Lower Silurian period, and 
* See this Jo i 
urnal (2), vol. xxiii 31, Proceedings of the Royal Society for 
May 1, 1857, and ne ee Peclogical Survey, cited below, p. 477. 
SECOND SERIES, VOL, XXV, NO. 74.—MARCH, 1858. 
: 28 
