American Geology, by T. 8. Hunt. 403 
To the southeast of this great fault in Canada we have as yet 
no evidence of Lower Silurian strata higher than those of the 
Quebec group. At the eastern base of the Green mountains, we 
find limestones of upper Silurian and Devonian age reposing 
unconformably upon the altered strata of the Quebec group, 
themselves also having undergone more or less alteration. Im- 
mediately succeeding are the chiastolite and mica slates of Lake 
St. Francis, which as we have long since stated are probably 
also of Upper Silurian age. 
T bite mountains as we suggested in 1849, (this Journal, 
[2], ix, 19), are probably, in part at least, of Devonian age, an 
are the representatives of 7000 feet of Devonian sandstone ob- 
served by Sir William Logan in Gaspé. Mr. J. P. Lesley has 
more recently, after an examination of the White mountains, 
shown that they possess a synclinal structure, and has adduced 
many reasons for regarding them as of Devonian age. (Amer. 
Mining Journal, Jan. 1861, p. 99). 
t will be seen from what has been previously said that we 
look upon the 1st and 2d divisions described by Mr. Safford in 
Eastern Tennessee, as corresponding to the hypozoic series of 
Rogers and to the Green mountain gneissic formation, w ich 
instead of being beneath the Silurian series, is really a portion 
of the Quebec group more or less metamorphosed, so that we 
recognize nothing in New England or southeastern Canada 
lower than the Silurian system, nor do we at resent see any 
evidence of older strata, such as Laurentian or Huronian, in an 
part of the Appalachian chain. The general conclusions whic 
we have previously expressed with regard to the lithological, 
chemical and mineral relations of the Green mountain rocks 
Laurentian, and Cambrian (Huronian) systems, overlaid by 
quartzites containing Scolithus, to which succeed limestones con- 
taining a numerous fauna, identified by Mr. Salter with that of 
the Chazy limestone. These strata, with an eastward dip, are 
covered by other quartzites and limestones, to which succeeds 
the great gneissoid formation of the western Highlands, consist- 
ing of feldspathic, chloritic, micaceous, and talcose schists resem- 
bling closely the gneissoid rocks of the Green mountains, and 
including the chromiferous ophiolites of Perthshire, and 
the Shetland Isles. ee 
This gneissoid series was by Prof. Nicol suggested to be the older 
or Laurentian gneiss brought up by a dislocation on the east of 
the Silurian limestones, but Sir Roderick Murchison, with Messrs. 
rkness, has shown not only from the differences 
in lithological character, but from actual sections, that the eastern 
