
QUEBEC GROUP IN GEOLOGY, 2: 
transverse sections of Sutton mountain, and these appear to me to proclaim in the most 
unmistakeable manner the simple anticlinal structure and, therefore, the superior position 
of the black slates and magnesian rocks on either flank of the mountain, and which latter 
certainly do present the precise phenomenon of distribution which Sir W. Logan says 
(page 251) they should do if the “ mountain were composed of strata lower than the Quebec 
group,” the zones of clay-slate spoken of being limited on the west by the unconformably 
overlying Cambrian and Cambro-Nilurian, and on the east by the also uncomformably over- 
lying Silurian, both sections holding in abundance their characteristic fossils. 
The colored map now first exhibited, but not yet published, shews with approximate 
accuracy the respective limits of the three groups. Their lithological characters are fully 
described in the Geology of Canada, 1863, chapter xix, and in earlier reports of the Survey, 
and I need only say that the oldest group includes the whole of the magnesian and hydro- 
mica slate belts, consisting of a great variety of crystalline and sub-crystalline massive and 
schistose metamorphic rocks,—the metamorphism or alteration often consisting in a decrys- 
tallization and in the assuming of a schistose structure. 
A small series of the rocks of each group is exhibited for the examination of the 
members of the section, and a much larger series can be studied in the Geological Museum. 
Referring again to the maps constructed prior to 1870, it will be seen that the strata com- 
posing the different groups have been assigned by perfectly imaginary lines to the Levis, 
Lauzon and Sillery formations of the Quebec group. I call the lines imaginary because 
they are found to cross and recross in the most arbitrary manner from the fossiliferous to 
the metamorphic belt, and also the line which is correctly described (page 256 of the 
Geology of Canada, 1863) as “the general course of the magnesian rocks for forty-five miles.” 
This course I have marked by a blue line on both the maps exhibited. 
- The only apparent principle adopted in tracing the divisions named seems to have 
been to make all areas of dark-coloured shales and slates, with dolomites, limestones and 
shists, Levis; red and green slates, unaccompanied by sandstones and cupriferous strata, 
Lauzon ; and an immense variety of rocks, including quartzites, sandstones, red and green 
slates, chloritic schists, gneisses, granites, diorites, diabases, felsites, serpentines, conglome- 
rates, and breccias or agglomerates, Sil/ery,—the same principle having been applied to 
both the fossiliferous and to the metamorphic belts. But even this principle has not been 
adhered to where it would not agree, as was often the case, with the supposed anticlinal 
and synclinal folds, as represented on section No. 1. In section No. 2, what appears to 
me to be the true structure is represented, the outline being the same as in No. 1. This 
shews a simple anticlinal axis, in accordance with the description (page 251, Geology of 
Canada) already quoted. The only objection, if indeed it be one, to this explanation of the 
structure is the great thickness which must then be assigned to these lower metamorphic 
rocks, not much less than 50,000 feet, supposing there are no repetitions by folding or 
faulting—a question, however, on which the evidence is not sufficient to warrant any 
decided opinion. Though knowing, as we do, that the district is traversed from NE. to 
S.W. by a number of great breaks, it is more than probable that many such repetitions of 
outcrops occur, making the real thickness considerably less than that deducible from the 

observed dips. 
I now come to the consideration of the second point, namely, the character and rela- 
Sec. IV., 1882. 2 
