T. S. Hunt on Ophiolites. 219 
my in getting an idea of the mode of formation of serpentine 
TOCKs 
The ophiolites of the Green Mountains often contain diallage, 
and more rarely actinolite and garnet. Calcareous, dolomitic 
rom the township of Orford, where these rocks are very exten- 
sively displayed, has furnished me with a large number of the 
Specimens about to be described. 
i@ analysis of the serpentines was generally effected by 
treating the mineral in‘ fine powder with sulphuric acid diluted 
with its own volume of water, and heating the mixture in a pla- 
tinum capsule until acid fumes were evolved; it was sometimes 
Ty to repeat this process with the undissolved residue. 
The purity of the separated silica was in all cases determined 
by dissolving it with the aid of heat, in a solution of carbonate 
of soda, The action of a boiling solution of nitrate of ammonia 
ron the mineral, either before or after ignition, was generally 
recourse to for the determination of any earthy car . 
color deep olive-green with small bluish veins; it was sub-trans- 
hone, aud wr highly argillaceous odor. This serpentine 
Ids in very small quantity, disseminated grains of magnetic 
" ; ' ‘ 0°30 
Magnesia (by difference), ‘i B ; : . be | 
; oxyd of iron, - ' 4 id “26 
xyd of nickel, - > ’ 
nf ahvewe, " -< ‘ . : ager 
Water, by ignition, - ; i : 0000 
rv 
2. A fraem entine. from a conglomerate dolo- 
Mitic ophiolte about tbe dameaitiad had a density of 2-622, a 
ackish- n color, a eonchoidal fracture, and was almost 
“Que. The pulverized and ignited mineral yielded to nitrate 
ammonia, 0-40 of carbonate of lime and 0°27 of carbonate of 
