48 ROYAL SOCIETY OF CANADA 
The underlying formation is clearly defined by beds of marine 
limestone which contain characteristie fossils of lower Carboniferous 
age. The rocks of this series differ in character from those of the 
interior Carboniferous basin and as a rule can be readily separated. 
The strata seen around the shores of Grand Lake, as also to the 
south and west, and along the Intercolonial railway which traverses the 
eastern portion of the province, present features similar to those found 
in the Millstone-grit of Nova Scotia. In the Report of the Geological 
Survey for 1872-73, on the rocks of the Grand Lake basin, the thickness 
of these Carboniferous rocks was estimated at not more than 600 feet, 
which, on quite insufficient data, was divided into three portions of 
200 feet each, representing the Millstone-grit, the Productive measures 
and the upper Carboniferous. This division was made chiefly from the 
evidence of the few plant remains collected, and need not be regarded 
as absolutely correct. 
The disparity in thickness thus given for the Carboniferous rocks 
in New Brunswick and that given in Logan’s section for Nova Scotia is 
very marked. The Productive measures were so called simply from the 
finding of the coal beds in the Grand Lake area, but similar thin coals 
are found at different places all round the main basin, varying in thick- 
ness from a few inches to a foot or more, in which the inclosing strata 
unmistakably belong to the horizon of the Millstone-grit. The presence 
of certain interstratified red or purple sandstones and shales in the 
Grand Lake area, which were supposed to indicate rocks of upper Car- 
boniferous age, is rather indicative of the Millstone-grit formation. 
They do not resemble the beds of the upper Carboniferous formation 
which are seen along the shores of Northumberland Straits, where they 
apparently form the western margin of that formation as developed in 
Prince Edward Island. 
On the assumption that the coals found on Coal Branch in Kent 
county, near the Intercolonial railway are the equivalents of those seen 
in the vicinity of Grand Lake, which they greatly resemble, the thick- 
ness of the underlying or rather containing formation should not be 
great at that point. At Grand Lake, however, it is probable that the 
underlying portion of the Millstone-grit is not wholly represented, 
owing to the masses of Devonian slates which rise as islands in the old 
Carboniferous sea. It is likewise probable that a low anticline traverses 
that portion of the province from the head of Grand Lake to the 
vicinity of the coal crops in Kent county, so that the outcrops at the 
two places are presumably on the same general horizon. 
DE Oh lO ele 
