in the Geological History of North America. 345 
The Azoic, as has been indicated, has something of a V shape, 
(or \v), with Hudson Bay between its arms. This succeeding 
step of progress is the partial development of a larger V outside 
of and parallel to the Azoic nucleus. The channels alluded to 
lie between the two V’s. The bar of the outer V on the left is of 
great breadth and made up of several broad parallel bands or 
ranges of elevations; that on the right is quite narrow compar- 
atively, yet also etched in several parallel lines. 
exican Gulf is all that remains of the larger of these 
channels. Its waters once stretched to the Arctic Sea, and were 
line of freshwater lakes along its former course; and the Gulf 
reached no higher than the headwaters of the Missouri, Later 
largest lake, Lake Superior, is at the junction of the two lines. 
Such was the law of growth. The molecular forces beneath 
the continent, from the progressive cooling there going on, were 
not idle, and must have modified the results. ‘But the main 
action causing the lifting and sinking of the crust and the final 
oe to the land, proceeded from the directions of the oceans. 
rocks were deposited, it 
elevated the continental border at least two or three thousand 
feet—ten times beyond what happened on the Atlantic side.t 
to the cause, there can be none as to the actu- 
c. The elevation of 
relative extent and 
exe 
the 
th i engge 
the southeast ; and the several parallel ranges on the Pacific side, parallel to the 
SECOND SERIES, VOL. XXII, NO. 66.—NOV+y 1886. 
44 
