340 Lf. E. SAVAGE 
Camarotoechia? winiskensis, Isochilina grandis var. latimarginata, 
and Leperditia hisingert var. fabulina in the regions above described 
it is inferred that during the time these strata were laid down the 
above-mentioned regions were a part of the same province or basin 
of deposition, which was rather broadly connected northward with 
the Arctic Ocean. 
This extensive northern invasion, together with the nearly 
synchronous deposits of the Cataract formation in a basin con- 
nected eastward with the Gulf of St. Lawrence region, and of the 
Brassfield and Sexton Creek limestones which were deposited in a 
southern basin, indicates a much more extensive submergence of 
the continent during early Silurian (late Alexandrian) time than 
was formerly supposed. 
The very close correspondence of the middle and late Ordovician 
and early Silurian rocks and faunas in the Saskatchewan and Hud- 
son Bay regions is strong evidence that they were deposited in a 
sea that was continuous between these areas. The presence of 
middle Ordovician and early Silurian rocks and faunas in the Lake 
Timiskaming region’ similar to those in the Hudson Bay region, 
and of late Middle and Upper Devonian strata in the vicinity of 
James Bay which probably originally extended south to the Timis- 
kaming region,” indicates that this part of the ancient Laurentian 
or Canadian shield did not exist continuously as a land surface 
throughout the Paleozoic era, as has generally been assumed, but 
that during middle and late Ordovician time, in early Silurian, 
and probably also during late Middle and Upper Devonian time 
the northern seas, temporarily at least, covered the greater part of 
this shield on the south and probably also on the west of Hudson 
and James bays. Kindle and Burling’ have previously shown that 
the seas probably also extended widely over the Laurentian upland 
southeast and east of Hudson Bay during the Paleozoic era. 
1M. Y. Williams, ‘‘The Ordovician Rocks of Lake Timiskaming,” Geol. Surv. of 
Canada, Mus. Bull. No. 17 (Geol. Series No. 27), June 7, 1915. 
2G. S. Hume, ‘Paleozoic Rocks of Lake Timiskaming Area,” Geol. Surv. of 
Canada, Sum. Rept. (1916), p. 190. 
3. M. Kindle and L. D. Burling, “‘Structural Relations of the Pre-Cambrian and 
Paleozoic Rocks North of the Ottawa and St. Lawrence Valleys,’ Geol. Surv.. of 
Canada, Mus. Bull. No. 18 (Geol. Series, No. 28), July 23, 191s. 
