178 TllC A III eric (1)1 (Icoloijisl. Marcli. 1S95 
I'eet or more, before the eastward iii)lift took ])lace. (c) The 
absence of a rock g'orj^'e at Saiilt Ste. Marie sliows that the 
rapids at that |»]ace are a comparatively new feature. These 
several conclusions taken t(>f;"ethcr put the date of the east- 
ward uplift a considerable time after the extinction of lake 
Algonquin. 
7. Vov a long period prior to the change of the outlet, the 
channel of Niagara river was occupied by the comparatively 
small Erigan river which drained only lake P^rie. This stream 
cut the gorge of the rapids below the cantilever bridge. When 
the St. Clair outlet opened, the greater cataract of Niagara 
began at a point a few rods above the cantilever bridge and 
since that time has cut back without interruption to its pres- 
ent place. 
S. When the eastward uplift began, it raised the outlet of 
lake Erie at Butt'alo and drowned that lake and also the south 
end of lake Huron, with the St. Clair and Detroit rivers and 
lake St. Clair. The simple northward elevation had previ- 
ously produced a change of this kind on the shores of lake 
Erie, but in onl}^ a slight degree. The former change brought 
about the building of the upper 25 or 30 feet of the St. Clair 
delta. 
9. The absence of a reeentl3' abandoned, northwardly rising 
beacli on the west shore of lake Michigan, between the node 
line and the Port Huron axis, points to an eastward rather 
than a northward uplift as being the latest phase of change. 
10. Many suggestive facts point to a correlation of the 
eastward uplift which deformed the Nipissing plane with the 
elevation of the northeastern barrier of lake Ontario and of 
the deposits of the Champlain submergence in the Champlain, 
lower vSt. Lawrence, and Hudson bay areas. 
From the study of lake Algonquin and the earth-movements 
which have deformed its water plane, we are led to a few 
other obvious conclusions of a wider sort. Geologically, the 
lake itself was a very recent thing. But the great Champlain 
uplift which introduced the eastward element of deformation 
was still more recent. When we reflect on the great magni- 
tude of the earth changes involved, both in their amount and 
areal extent, their recentness in time becomes more and more 
impressive as a lesson in the p.Qssibi.lit;ies of late geologic his- 
