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find that it is made up of several large basins in which are 
still found numerous lakes, mostly fresh, but often brackish 
or saline, which commonly have no outlet, but, on the con- 
trary, have draining into them numerous small streams, 
which must bring down into these lake beds, the saline 
materials they have washed down from the surrounding 
country. But this is evidently not the way in which these 
saline lakes have been formed, but in my opinion in the 
following manner. 
In former times the Rocky Mountains constituted the coast 
line of the Pacific Ocean and during the period whenits waves 
beat upon those rocky slopes there were to the east of them 
large accumulations of fresh water in the form of seas of 
much greater dimensions than the mighty lakes which now 
wash our northern borders. Insuch lakes, of course, lived, in- 
creased and died numerous species of fresh-water Diatomacez, 
which as they perished and their remains accumulated on 
the beds of these seas were stored up as enormous Lacustrine 
Sedimentary deposits. In time the western coast of the 
North American continent began to rise still farther up and 
as this was progressing, islands were thrown up all along and 
parallel to the coast, mainly by the upheaving action of 
submarine volcanoes. Perhaps in some cases, these volcanoes 
broke forth in these islands, but this was evidently not 
commonly the case, there being no craters formed until 
some time subsequently. Gradually, however, these islands 
were pushed farther and farther upwards until, at last, a new 
coast-line was formed, the space intervening between it 
and the old coast being raised so gradually that the salt 
water was all drained off and dry land appeared. Now 
would seem to have been a period of comparative rest, dur- 
ing which the mountains of the new coast and those which 
constituted the former coast poured down their drainages 
into the new basin and rivers and lakes were formed; in 
which, as before, Diatomaceze appeared and accumulated. 
Whilst this was occurring inland, a new coast was again 
preparing and this state of things was to be repeated 
at shorter and shorter intervals, and perhaps, and most 
