216 REPORT ON CORRELATION 
and the Grenville series. Now that investigations have shown that 
these two series differ in origin, one being essentially a great develop- 
ment of very ancient sediments, and the other consisting of great 
bodies of igneous rock intruded through them, it becomes necessary 
to separate these two developments in drawing up a scheme of classi- 
fication. 
As the great intrusions of gneissic granite, forming what has been 
termed the ‘‘fundamental gneiss,” have an enormously greater areal 
development than the overlying sedimentary series, constituting, 
as they do, a very large part of the whole northern protaxis, the 
committee recommend that the term “Laurentian” be restricted to 
this great development of igneous gneisses. The nomenclature 
suggested for the pre-Cambrian rocks of this eastern region will 
thus conform, so far as the use of this term is involved, with that 
suggested by the Special Committee for the Lake Superior region.* 
For the overlying sedimentary series the committee recommend 
the adoption of the name “Grenville series,” as it is the name origi- 
nally given by Logan to the series as typically developed about the 
township of Grenville in the “Original Laurentian area” on the 
north shore of the Ottawa River, in the Province of Quebec, between 
the cities of Montreal and Ottawa. The term “Hastings series” in 
the opinion of the committee should be abandoned as a serial name, 
seeing that the development to which this name was applied by Logan 
is merely the Grenville series in a less altered form, as Logan in giving 
the name had conjectured was probably the case. ‘The committee, 
however, think that it may in some cases be advantageously employed 
as a qualifying term to designate the less highly altered phase of the 
Grenville series, which may thus be referred to as the “Hastings 
phase” of the Grenville series. 
In Canada this Grenville series everywhere on going north is 
invaded by and frays away into the great Laurentian bathyliths, 
while in the Adirondacks it is cut to pieces by the great intrusions of 
that area which, when worked out in detail, may prove also to have 
a more or less similar bathylithic form. 
The following succession in this region is therefore recognized 
and adopted by the committee: 
t See Journal of Geology, February—March, 1905. 
