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the lamented Rémond, Drs. Shiel, Wislizenus and others. 
Besides Mr. Clarence King has explored a large tract of this 
country but his very important contributions have not, as 
yet, been made public. 
~The general character of the topography of the region west 
of the Mississppi has been given by these great lines of eleva- 
tion traversing the country from north to south, There are 
the Rocky Mountains, the Sierra Nevada and the Coast 
Ranges. The last is the most modern, and is composed, for 
the most part, of Miocene Testiary rocks. Parallel with this 
hes a narrow trough, in California traversed by the Sacramento 
and San Joachin Rivers, encroached on by the mountains at 
places, but still in Oregon and Washington, trayersed by the 
Willamette and Cowletz Rivers. (These two sections are 
drained through the Golden Gate and Columbia. The moun- 
tain barriers formerly caused the valleys to consist of great 
inland lakes which are now only represented by the chain of 
small pieces of water still to be seen in that region of country. 
Kast of the Sierra Nevada and between it and the Rocky 
Mountains is another still larger basin. For a thousand 
miles it has no openings to the westward which are less than 
five thousand feet above the sea, but at three points there are 
gate-ways, which may be passed, but httle above the sea 
level. These are the Cafions of the Sacramento (Pit River) 
the Klamath and the Columbia. These have been eut 
through by the drainage of the interior of the continent. 
The former beds of the lakes have thus been left dry and 
waste—the only real desert on the North American conti- 
nent. The Sierra Nevada is older than the Coast Ranges | 
and projected above the ocean, though not to its present 
altitude, previous to the Tertiary and even Cretaceous ages. 
This we learn from the fact that strata belonging to these 
formations cover its base. The mass of the Sierra Nevada is 
granitic rocks and metamorphic slates, proved by the Califor- 
nia Survey to be Triassic and Jurassic. These slates are 
traversed by the gold-bearing Quartz. 
Hast of the Sierra Nevada is a high and broad plateau five 
hundred miles wide, and from four to eight hundred feet in 
