SECTIONAL TRANSACTIONS.—C. 389 
the Timiskaming region, to which, because of their proximity, they are probably 
most closely related. 
The formations of the Grenville subprovince in Ontario and Quebec, except 
for the unconsolidated Pleistocene and recent deposits and a few intrusions of 
lamprophyre, diabase, granite, and syenite, of late Pre-Cambrian age, all belong 
to a typical basal complex. This constitutes the Laurentian of Logan, and 
because of its highly metamorphosed condition has always been regarded as 
early Pre-Cambrian in age. The formations ars in some respects the same 
throughout the whole region, but certain differences exist between its western 
anc eastern parts, as shown in the following tabular statement of the succession 
of formations in each. 
| WESTERN PART EASTERN PART 
a (South-Eastern Ontario) (Quebec) 
Hite - 
oes) F : 
| as Grenville and Rigaud stocks of 
4 Ss granite and syenite 
FS Diabase dykes Diabase dykes 
Ay 
Lamprophyre mass and dykes 
| 
Granite, granite Granite, granite 
Batholithic ] Eneiss and Batholithic | £neiss, and 
intrusives Byenite ain d intrusives Byeni ia and 
syenite gneiss eae gneiss 
Pegmatite, 
Besiinetans shonkinite, 
Gabbro and diorite epee am | pyroxene diorite, 
: norite, 
z Ggneous) [mortosite, 
2 35) peridotite, &c. 
Soa 
Gx 
pq , Limestone, dolomite, 
S83 Hasnee | argillite, greywacke, 
a S | and conglomerate 
| 
a a Crystalline limestone, . ( Crystalline limestone, 
Ay r= G ill dolomite, quartzite, pc! oy sillimanite-garnet 
ws pila Ki ©) mica schist, silliman- ere | gneiss, and quartzite 
3 3 4 aa gneiss, and 
a lava flows 
a 
The formations occurring in the Grenville and Timiskaming belts are, for 
the most part, lithologically unlike, so that in attempting their correlation 
several hypotheses must be considered. Of these the most important are the 
following : (1) that the Hastings or Hastings and Grenville series are entirely 
or in part equivalent in age to the Huronian, a possibility suggested to the 
writer several years ago by W. H. Collins and recently advocated by Quirke; 
(2) that the batholithic intrusions of granite and granite gneiss occurring in the 
two regions are of the same or about the same age; (3) that the Grenville series 
is of about the same age as the Abitibi (Keewatin of some writers) group; 
(4) that the Hastings series is correlative with the belts of sediments classed 
as Timiskaming in the Timiskaming belt; and (5) that the Grenville or Grenville 
and Hastings series are older in age than the Keewatin group. 
Evidence for and against these possibilities is presented. 
