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likely, with more and more violent commotions, new 
ranges of mountains with basins intervening were formed 
until we had what we now find; the Rocky Mountains as 
the first coast line with the remains of vast inland fresh- 
water seas still remaining, but for the most part dried up; 
then the next coast line is the Cascades and Sierra 
Nevada pierced by numerous Volcanic cones, some of them 
still in action, or, at least, very recently so; and between 
these two lines again the vast deposits of Diatomacex I have 
mentioned. Subsequently, and at shorter intervals, we have 
the three or four ridges, which together, are included under 
the head of the Coast Range; whilst, in turn, we have a 
new coast, now in progress of formation and making itself 
evident in the plainly rising islands lying just off and paral- 
lel to the coast. In truth, it is a well-known fact, that the 
whole of our Pacific coast is rising and with a celerity recog- 
nisable within the scope of the last one or two generations of 
man. So, I think I have shown pretty plainly how the 
parallel ranges of mountains were formed and how the im- 
mense deposits of Diatomacez accumulated. But why do not 
these latter appear at the present time as Lacustrine Sedimen- 
tary material containing a certain amount of organic matter ? 
For the reason that in every case they are overlaid by and often 
interstratified with Lava or Trap which has burned out all 
the originally-existing organic matter and consolidating the 
siliceous remains has left them in the form of a hard, white, 
stony mass. The interstratification, in one case at least, as 
often as seven times, of this material with Lava, shows that 
this country has been subjected to repeated volcanic convul- 
sions during which Lava has flowed into and obliterated to 
a great extent, these lakes. Perhaps thereafter, in each case 
there was sufficient subsidence to permit of the accumulation 
of water again so as to form’a lake. But I think that I have 
made this point clear and I will leave it here, only calling 
attention to the fact that besides Sub-Plutonic deposits, 
which we could have no where else in the world that I am 
aware of—as no where else do we have precisely the same 
geographical and geological attendant circumstances—in the 
EEOC. LYC, NAT. HIST. N. ¥.—VOL. 1. 9 
