404 
massive fossiliferous rocks of the Queen 
Charlotte islands and Kootanie formations 
were accumulated and coal beds were pro- 
duced. Voleanie activity was renewed in 
some places, particularly near the present 
seaward margin of British Columbia. Sedi- 
mentation evidently proceeded more rap- 
idly than subsidence in many localities and 
coal-producing forests, largely composed of 
cycadaceous plants, took possession of the 
newly formed lands from time to time. 
The era of later Cretaceous appears, how- 
ever, eventually to have been introduced 
by a marked general subsidence, which, as 
already noted, carried the Dakota sea en- 
tirely across the inland plain of the conti- 
nent. The distribution and character of 
the ensuing Cretaceous formations show 
that the whole southern part of what is 
now the mainland of British Columbia soon 
after became and remained a land area, 
while the sea was more gradually excluded 
from the northern part of the Cordillera 
and continued to occupy the area of the 
Great plains and the present position of the 
Laramide range. Along the margin of the 
continental plateau, however, a renewed 
subsidence was in the main progressing 
southward and resulted ultimately in car- 
rying the later Cretaceous sediments into 
the region of Puget sound. 
The closing event of this cycle was the 
deposition of the Laramie beds on the east 
and in some places to the north, with prob- 
ably the Puget group and its representa- 
tives on the coast, and this was followed 
by the most important and widespread oro- 
genic movement of which we find evidence 
in the entire Rocky Mountain region. At 
this time the great Laramide range, or 
Rocky Mountain range proper, was pro- 
duced, rising on the eastern side of the 
Archean axis along a zone that had pre- 
viously been characterized from the dawn of 
the Paleozoic by almost uninterrupted sub- 
sidence and sedimentation. That the pres- 
SCLENCE. 
[N.S. Von. XIII. No. 324. 
sure causing this upthrust of the Laramide 
range was from the westward is clearly 
shown by the great overthrust faults in 
thisrange. The stability of the old Archean 
axis, which if may be supposed had pre- 
viously sustained the tangential thrust irom 
the Pacific basin must at this time have 
been at last overcome. As a part of the 
result of this, the chief belt of faulted 
strata in the Laramide range, originally 
about 50 miles wide, became reduced in 
width by one-half. How rapidly this great 
revolution may have occurred we do not 
know, but it probably did not occupy a long 
time from a geological point of view, and 
the Laramide range, as first produced, may 
very possibly have attained a height ap- 
proaching 20,000 feet.* The thickness of 
stratified rocks in the geosyncline was at the 
time probably more than 40,000 feet. 
It is difficult to determine to what ex- 
tent the Archean axis with the Gold ranges 
and other preexisting mountains was af- 
fected at this period of orogenic movement, 
because of the absence of the newer forma- 
tions there, but it seems probable that no 
very important change took place. Far- 
ther west, however, the great zone of Coast 
ranges was elevated, and the corrugated 
and vertical Cretaceous beds, met with even 
on their inland side, show that large parts 
of the Interior plateau of British Columbia 
and of the country in line with it to the 
northward were flexed and broken. Sim- 
ilar conditions are found to have affected 
Cretaceous rocks of Vancouver and the 
Queen Charlotte islands, of which the 
* This refers particularly to the better known region 
near the Bow pass. See Annual Report, Geol. Sury. 
Cai. (N. S.) Vol. IL, p. 31 D, and Am. Jour. Sci., 
Vol. XLIX., p. 463. The base of the mountains may 
at this time have been nearly at sea level, or 4,000 feet 
lower than at present, while the actual height at any 
time attained would depend upon the rapidity of up- 
lift relative to denudation. The total height of 
folded strata is estimated at from 32,000 to 35,000 
feet. 
