CARBONIFEROUS STRATA IN THE MARITIME PROVINCES. 189 
they are at least 3,000 feet thick. In Pictou County these measures seem to graduate insen- 
sibly into the Millstone Grit, but I have measured a thickness of 3,000 feet of what appear 
to be undoubted Carboniferous limestone measures. In Antigonishe County they present 
an undulatory appearance, which renders any computation of their thickness uncertain ; 
it may, however, be considered not less than 3,500 feet. In Richmond and Inverness 
Counties they are again presented with the characteristic limestone and gypsum, overlaid 
by black and gray shales, with calcareous bands. Their thickness appears to diminish to 
the east, through Lock Lomond and Salmon River, until the Sydney district is reached, 
where it attains nearly 2,000 feet. In Newfoundland Mr. Murray has placed its thickness 
at 2,150 feet. 
We find that the point of maximum depression is in the Richmond district, and that 
it gradually diminishes each way toward the north-west and the north-east, reaching the 
minimum in central New Brunswick, and increasing again in the Tobique district, and in 
northern New Brunswick. 
Along certain lines in New Brunswick, the south part of Pictou County, at Arisaig, 
and in part of Inverness County, are contemporaneous injections of igneous rocks. They 
are not noticed in Cape Breton County, nor, so far as I am aware, in Newfoundland. 
Along the flanks of the Boisdale Hills, and at other points in Cape Breton, these strata 
were indurated, folded and elevated, so as to furnish materials for the succeeding Mill- 
stoneGrit. In southern New Brunswick these measures were folded along the coastal range 
toward their close, the disturbance being ended before the Millstone Grit period. 
The whole district during this period appears to have been subjected to a long con- 
tinued depression of very equal amount, forming what might be termed a continental sub- 
sidence. The date of its cessation would probably be marked by the foldings in Cape 
Breton and southern New Brunswick. In the northern part of the latter Province, this 
horizon shows by its comparatively undisturbed condition, and by its marks of slight 
unconformability to the succeeding measures, that there has been little violent change 
since the date of its deposition. 
THE MILLSTONE GRIT SERIES. 
In central New Brunswick there is a set of measures not exceeding, I believe, 1,000 
feet in thickness, which follow the representatives of the Carboniferous Limestone with 
slight marks of local unconformity. In their lower part they present a Millstone Grit facies, 
in the upper part the presence of a persistent coal-producing horizon would, perhaps, indi- 
cate the formation of the productive measures. However this may be, the purposes of 
this paper will be answered by considering it as a whole. For it shows that since the 
beginning of the Millstone Grit epoch this district has suffered but slight movement (it now 
presenting a series of low undulations, and a general horizontal position), and that the 
changes of level have been comparatively insignificant. 
Along the coastal range the Millstone Grit series were spread over the folds of the 
preceding Carboniferous measures, from which, doubtless, was derived a portion of the 
material composing them. I have measured a thickness of 950 feet of Millstone Grit strata 
in the Dorchester district, but this may be exceeded at other points. 
Following these measures across the great Amherst anticlinal, we find them regularly 
