Modern Igneous Rocks and the Primary Formations. 127 
teen degrees. But the inclination may have been still more 
gradual from the centre outward. The only point which I would 
sustain, is that the region in Northern California alluded to is a 
region of granitic eruptions, the granite peaks its centre, the jasper 
its outer borders. 'There may be many other centres in the same 
mountains, as volcanoes are sometimes crowded together, but in 
a hasty jaunt this could not be ascertained. Passing in only a 
single devious course through the region, it is impossible to esti- 
mate its extent. ‘The jaspers were first met with about eighty 
miles from the granite. 
The facts that have been presented lead us in conclusion to the 
following general views with reference to the earlier condition of 
our globe. I enter into no speculations with regard to the come- 
tary nebula which .has been supposed its condition when it first 
begun its revolutions in space: neither would I go back to the 
time when, according to some, it was a fluid mass resting beneath 
heavy vapors ready to settle upon its cooling surface—a supposi- 
tion, by the way, no more hypothetical than that assuming the 
earlier rocks to be the remoulded material of another world—I 
come down to the era when the ocean existed. Igneous action 
was no doubt rife in those times, for however much we may wish 
to disbelieve it, there is evidence in almost every volcanic region, 
and especially such immense tracts as those of the East Indies 
and the Andes, that the present are comparatively quiet times. 
In the early age to which allusion is made, igneous action ex- 
ceeded beyond doubt any thing of later date. "These were times 
of extensive granitic eruption. Centres of igneous action were 
scattered over the earth or arranged in lines the sites of former 
fissures ; for in almost all modern igneous regions a linear arrange- 
ment may be distinguished. From these centres or central re- 
gions, granite was poured out along with gneiss, syenite or some 
of the allied rocks; the ocean was agitated with repeated shocks, 
and heated by the opened fires; sands were shivered or worn 
from the ejected rocks and scattered far and wide around the 
place of eruption by the troubled sea; and after deposition, the 
permeating and superincumbent waters heated from the same 
or a subsequent eruption, finally recrystallized the deposits and 
studded them with new gems, or modified their composition 
through the magnesia, silica and other substances held in so- 
lution. ) 
‘ 
