Rocky Mountain Trio 
40 
twelve miles away by 11 o f clock - .a fine, large river but a good 
ford. We cross It in a broad valley with slight terraces on the 
sides. In the bluffs about are the outcroppings of the tertiary 
sandstones. Leaving the Eio we cross a sago flat and roar eh up 
a wash and turning over a low ridge to the north pass through 
the Great- Hogback into the valley of the cretaceous shales and 
by ?my of a fine canon out:by a large creek- the sandstones of 
, A . Jpp ■ ' • 
the Hogback are cretaceous^ some 3000 feet thick and corres'poiid 
i 
in horizon to the Mesa Verde series* The tertiaries outside are 
the same or closely resemble the tertiaries of the San Juan about 
the mouths of Lafl&ta and Anirme* The latter beds are her© nearly 
horizontal, while the sandstones of the Hogback, being firm and 
heavy, are turned up at & high mgle 70 to 80° and trend in a 
grand curve from the west slope of the Elk Mountains, around to 
the White Biver agency* The sandstones of this group seen much 
metamorphosed and. the coal seams too have been burned out, leav¬ 
ing red bands containing cinder# etc. A valley eroded from the 
* 
cretaceous shales extends -along the east base and form a natural 
pass from the Grand and White river. A dome plateau, outlined by 
Ho * 1 and filled in with red beds# etc.# lies still to the east 
of this low valley. An intense deal of the drainage of this 
plateau gathers in this narrow valley and passes out thro ugh 
the canon gateway mentioned above* 
Sopt. 50th ? Waite Elver Agency* 
