GEOLOGY—WESTERN RANGE OF SIERRA NEVADA. 
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limit, and that anterior to the emergence of the Californian valley or the coast mountains, the 
ocean dashed its waves against a continuous iron-bound coast, formed by the great Californian 
range. Of this coast Mount Shasta was a high and prominent headland. 
With the subsequent elevation of the coast mountains, the entire western portion of the con¬ 
tinent was doubtless considerably raised, and, like the higher, the lower terrace was bordered 
by mountain ranges, which presented to the Pacific a second continuous wall, on which its 
waves, though borne on by all the accumulated momentum of their long and unobstructed 
course, are still impotently beating. 
I think we have evidence, derived from various sources, that the elevation of the western 
coast continued long after it reached the present level, and that since its maximum height 
was attained it has suffered a depression of many hundred feet. I shall, however, have occasion 
to return to this subject when speaking of the Cascade mountains, and will, therefore, leave it 
till the facts there to be gained can be brought to bear upon it. 
The continuity of the present coast mountains of California and Oregon can scarcely be 
doubted. The fossiliferous sandstones of Monterey, Santa Clara, San Francisco, Port Orford, 
Coose bay, Astoria, and the Cowlitz, are all apparently of the same age. Though presenting 
marked local peculiarities, they have a common character both in their lithological features and 
in their fossils, and are to be referred to a common period—certainly not older than the 
Miocene. 
In going from the mouth of the Columbia to San Francisco by sea, the coast seems formed of 
a continuous mountain chain, which is constantly in sight, and which produces, throughout 
nearly the entire distance, a bold, rocky, “ iron-bound” shore. To this general rule the limited 
areas of level land in the valleys of the Umpqua, Coquille, Eogue, and Klamath rivers, form 
scarcely an exception. 
As far north of San Francisco as Cape Mendocino the coast mountains have the same general 
northwest trend ; and a more plausible supposition than that the Cascades form the continuation 
of the coast mountains would be, that the latter ranges terminate at Cape Mendocino, and that 
the coast mountains of Oregon were a continuation of the Sierra Nevada. It is not necessary 
to suppose this, however, but it is sufficient to consider the coast mountains of Oregon as the 
coast mountains of California deflected from the trend which they preserve below Cape Mendo¬ 
cino, and that the ranges of the coast and of the interior inosculate on either side of the parallel 
of 42° in the Calapooya, Umpqua, and Siskiyou mountains. 
The structure of these subordinate ranges has as yet received but little attention from geolo¬ 
gists, though it presents some very interesting problems, which, aside from their bearing on 
the local geology of the far west, will perhaps throw some light on the question of the synchon- 
ism of parallel axes of elevation, and the constancy of trend in the same line of upheaval. 
Nor is the question of the relations of Mount Shasta to the coast mountains or Sierra Nevada 
one of merely abstract interest, but of the highest practical value in determining the relative age 
of these two mountain systems, and especially in fixing the age of the metamorphic limestones 
and slates of the Sierra Nevada, which as yet have yielded no fossils. If, as seems probable, 
the fossiliferous limestones of the mountains connected with Mount Shasta shall prove to be 
continuous with the limestones of the Sierra Nevada, referred to above, they will, perhaps, serve 
as a key by which to unlock the whole structure and age of the great “ Californian range.” 
