On the Serpentines of Canada and their associated Rocks. 889 
position in all the serpentines of this formation, and also show a 
curious fact hitherto overlooked,—that of the constant presence of a 
small portion of nickel, never exceeding a few thousandths. I have 
never failed to detect it in any variety of serpentine from this forma- 
tion, not only in Canada, but in the States of Vermont, Connecticut, 
and New Jersey. Its presence seems still more widely spread, for I 
have also found nickel in serpentines from California, the Vosges in 
France, and in a verde antique marble from a Roman ruin. The 
association of nickel with the chromic iron and serpentines of Penn- 
sylvania has been long known, and I have found the chromic iron of 
Canada to contain small portions both of nickel and cobalt, although 
the latter metal can rarely be detected in the nickeliferous serpen- 
tines. 
The results of a number of analyses show that it is constantly pre- 
sent in the talcose slates and steatites of this region, and the same is 
to be observed of the magnesites and dolomites of the series ; indeed 
the distribution of nickel would seem to be co-extensive with that of 
the magnesia in this formation, and the same thing may be said of 
chrome. I have not, however, met with any traces of chrome or 
nickel in the serpentines and talcose rocks of the Laurentian system, 
which underlies the Silurian and the still older copper-bearing rocks 
of Lake Huron, and probably corresponds to the oldest gneiss of 
Scandinavia. Both chrome and nickel, however, characterize the 
serpentines of the Vosges and of California. I have not yet been 
able to examine specimens from other foreign localities. ‘The pre- 
sence of traces of nickel in certain tales was long since noticed by 
Stromeyer. Much of the so-called talcose slate of the Green Moun- 
tains is not magnesian, but consists of a hydrous aluminous silicate 
allied to pyrophyllite or pholerite, which are alumina-tales. 
The euphotides, which are associated with many of the European 
serpentines, are not wanting in the Green Mountains, although less 
distinctly marked to the eye than the foreign varieties. A tough, 
greenish or greyish-white rock, with a waxy lustre, forms in many 
places great stratified masses, which are associated with the serpen- 
tine, and is found on analysis to consist of a soda-felspar (albite) 
with a silicate of lime, magnesia, and protoxide of iron, having the 
composition of amphibole,—thus constituting a veritable euphotide. 
The two minerals are clearly distinguishable after calcination, which 
blanches the felspar, and reddens the ferruginous silicate. These 
rocks are by this means distinguished from others similar in their 
appearance and mode of occurrence, but consisting of petrosilex or 
compact siliceous felspar, and equally members of the sedimentary 
series. The specific gravity of these euphotides shows that the 
saussurite or felspar which forms their base has a density not greater 
than that of ordinary soda-felspar. 
Immediately connected with the serpentines, there sometimes 
occurs a white compact rock, remarkable by its great hardness, and 
a density of 3°3 to 3-5. Analysis shows this rock to be a pure lime- 
alumina garnet, in some cases, however, mingled with another sili- 
cate which appears to belong to the amphiboles. This garnet is 
