244 F. V. Hayden on the Geology of the Country 
posits and Jurassic beds, and find no rocks that indicate deep 
water deposition. Cretaceous formation No. 1 commences in 
many places with a considerable thickness of an aggregation of 
water-worn pebbles passing up into thin alternate layers of are- 
naceous and argillaceous sediments with thick beds of sandstone 
with ripple markings and oblique laminee, then gradually ceases 
in No. 2 and through Nos. 2, 8 and 4, the sediments indicate 
that they were accumulated in comparatively deep and quiet 
waters. No. 2.is a black plastic clay, No. 3 grey marl, and No. 
4 a dark indurated sometimes Jaminated clay with many calea 
reous conerctions, In No. 5 we gradually approach indications 
of shallow water until dry land appears, as already stated. 
It will not be possible at this time to mention in detail all the 
oscillations of surface and other physical changes to which we 
have reason for supposing the country was subjected during all 
these periods. It is sufficient for our present purpose to show 
that except during the middle Cretaceous epoch no long continued 
periods of quiet water prevailed in these ancient western seas. 
The evidence appears to me to point to the conclusion that a 
much milder climate prevailed throughout the western portions 
of our continent, during a greater part of the Tertiary period 
than that which exists in the same latitudes at the present time. 
The organic remains appear to indicate a subtropical climate or 
one similar to that of our Gulf States. Near the close of the 
epoch. 
Again, he luxuriance of the flora which has been so perfectly é 
preserved in the lignite strata of the West point to the same 
conclusion. It is true that until recently no species have P 
) P' 
found which belong exclusively to a tropical vegetation, bat dur: 
ing our Jast expedition we obtain species of true fan pa 
. . 
34°- 
and of Chamerops humilis in Europe, near Nice, in 43°44" 
