od, throughout thé central portions of the continent, lakes, estu- ~ 
aries, &c., more or less salt, at length becoming brackish, and 
finally fresh water, existed, anda new flora and fauna were intro- 
duced. The subterranean expansive power which was quietly 
lifting up the country still continued, although no bursting of 
the earth’s crust had commenced. These brackish waier depos- 
| its which appear to mark the dawn of the Tertiary riod in the 
West, are distributed quite widely over the centra i 
: . the Rocky mountain district and then by a general subsidence or 
4 Vast increase of fresh water, the true lignite deposits zi 
themselves over large areas and probably covered much of the 
Sountry, now oceupied by the mountain ranges and were doubt- 
ag less more or less intimately connected with the Tertiary beds on 
the Pacific coast, What barriers separated them from the Ter- 
tiary formations along the Pacific—it is impossible from our 
Present limited knowledge of the geology of the intermediate 
ee i 
— mountain crests or ridges, oc¢ 
Si of the accumulation of the 
eve this for the following reasons. 
ee 
Wferous rocks, though, as a general rule, po 
remote from the axis of t 
