272 
BASALTIC ROCKS. 
cific shores and the islands, numerous volcanoes ; 
and it would be strange, indeed, if there were none 
within our extensive possessions on the same 
coast." 
There are numerous evidences of volcanic agency 
among the Rocky Mountains, such as extinct cra- 
ters, lava, scoriae, and other igneous products. 
" The whole country," says Mr. Parker,* " from the 
Rocky Mountains on the east and Pacific Ocean on 
the west, and from Queen Charlotte's Island on the 
north to California on the south, presents one vast 
scene of igneous or volcanic action. Internal fires 
appear to have reduced almost all the regular rock 
formations to a state of fusion, and then, through 
fissures and chasms of the earth, to have forced the 
substances which constitute the present volcanic 
form. Such has been the intensity and extent of 
this agency, that mountains of amygdaloid and ba- 
salt have been thrown up ; and the same substance 
is spread over the neighbouring plains, to what 
depth is not known ; but, from observations made 
upon channels of rivers and the precipices of ra- 
vines, it is evidently very deep. The tops of some 
mountains are spread out into horizontal plains, 
some are rounded like domes, and others terminate 
in conical peaks and abrupt eminences of various 
magnitudes, which are numerous, presenting them- 
selves in forms resembling pillars, pyramids, and 
castles. There are several regularly"^ formed cra- 
ters ; but these, presenting themselves in depres- 
sions or in cones, are rendered obscure by the lapse 
of time. That volcanoes have existed there can be 
no doubt, but that they have been in active opera- 
tion recently is more uncertain." Mr. Parker also 
states that nearly all the rocks among the Rocky 
Mountains are amygdaloid, basalt, lava, and obsidi- 
3,n (volcanic glass), which sufficiently prove the vol- 
canic character of this region. 
* Exploring Tour, &c., p. 208. 
