[amr] SYNOPSIS OF THE GEOLOGY OF CANADA 189 
The Acadian Region—The Laurentian system is well developed in 
many portions of Cape Breton, New Brunswick, and Newfoundland 
where it consists of granitoid and foliated gneisses and syenites. 
In New Brunswick crystalline schists of the Portland group, the 
felspathic and chloritic gneisses of the St. John region are assigned 
to this horizon by Dr. Matthew and Dr. Ells. The Boisdale and East 
Bay hills of Cape Breton are also referred to the Laurentian by Mr. 
Hugh Fletcher. From Cape Ray to Canada Bay and from Hermitage 
Bay to Cape Freels, two parallel belts of Laurentian rocks occur in New- 
foundland. 
The Laurentian Highlands.—Rocks of the Laurentian system con- 
stitute nearly nine-tenths of the area of the great peninsula of Labrador, 
and according to Mr. A. P. Low, consist for the most part of foliated 
hornblende and granite-gneiss, such as occur in the fundamental or 
Ottawa gneiss, overlaid by mica gneisses and mica schists belonging to 
the Grenville Series. 
In the province of Quebec, north of the island of Montreal, Dr. 
Adams informs us that the fundamental gneiss consists largely of 
igneous rocks, banded and foliated, owing to the movements and arrange- 
ment amongst the constituents caused by pressure. These gneisses are 
penetrated everywhere by other igneous masses, including the anorthosite 
rocks, belonging to the gabbro family, with plagioclase predominant. 
These latter constitute the Norian or Upper Laurentian of Hunt and 
older geologists, but are known to cut the Grenville series also referred 
to the Upper Laurentian and are therefore post-Grenvillian eruptives. 
In Central Ontario, Dr. Adams together with Dr. A. E. Barlow 
agree in the statement that the Laurentian gneisses occur in that pro- 
vince, and occupy a large portion of the area coloured as Archæan, where 
they consist of granitoid gneisses, diorites, and gabbros, all more or less 
clearly foliated. Associated with these gneisses, in the two areas last 
mentioned, there occur the Grenville and Hastings series respectively. 
These two are held to be probable equivalents and newer than the 
fundamental gneiss of the Laurentian. 
Dr. Barlow aptly describes the fundamental gneiss of the Lauren- 
tian as follows :— 
“It may possibly represent, in great part, the first-formed crust of 
the earth, which, necessarily thin and fragile, and so liable, to frequent 
upswellings of the molten mass beneath, has undergone successive fusions 
and recementations before reaching its present condition. As at present 
mapped, it is regarded as a complex of irruptive plutonic rocks, repre- 
senting repeated and intricate intrusions of basic and acidic material. 
