CHAPTER VIII. 
GEOLOGY OF REGION BETWEEN THE COLORADO AND FORT DEFIANCE. 
VALLEY OF THE LITTLE COLORADO AT CROSSING.—RED SANDSTONE FORMATION.—ITS PARALLELISM.— VARIEGATED MARLS.—PAINTED 
DESERT.—MESA WALLS OF RED SANDSTONE.—VARIEGATED MARLS —SECTION OF MESA BETWEEN LITTLE COLORADO AND MOQUI 
VILLAGES.—PARALLELISM OF GROUP OF ROCKS FILLING INTERVAL BETWEEN THE CARBONIFEROUS AND CRETACEOUS FORMATIONS.— 
TRIAS NOT IDENTIFIED.—DETAIL¥D SECTIONS OF THE VARIEGATED MARLS AND RED SANDSTONES —-SALT SPRINGS OF THE LATTER 
SERIES ILICIFIED WOOD OF THE BUTTES, CALLED RABBIT HILLS.— UPPER MAR —LIGNITE WITH FOSSIL 
PLANTS.—PROBABLY JURASSIC.—ERODED SAN NES NEAR MOQUI VILLAGES.—GEOLOGY OF THE MOQUI COUNTRY 
CRET. ILED SECTION OF CRETACEOUS MESA.—CRETACEOUS FO NORTH OF MOQUI VILLAGES. — 
UPPER CRETACEONS STRATA.—GEOLOGY OF NAVAJO COUNTRY.—PREVALENCE OF LOWER CRETACEOUS ROCKS.—FRESH WATER 
TERTIARY BEDS —-VALLEYS OF EROSION.—NAVAJO VALLEY.—CANON BONITO.—ANTICLINAL AXIS WEST OF FORT DEFIANCE.— 
ELEVATED AND INDURATED SALIFEROUS SANDSTONES. 
VALLEY OF THE LITTLE COLORADO AT CROSSING. 
The trough of the Little Colorado, from the cascades to the point where we left it, fifty miles 
above, is similar in all the general aspects of its structure to what it has been described to be 
further north, except that the stream has not so deeply eroded the strata here as below, and 
its bed is formed of a higher member of the geological series; the belt of low and level land 
which it includes is narrower, and the bluffs or walls bounding it much less imposing in their 
magnitude. 
The river is here scarcely depressed below the plain bordering it; the cafion which it 
traverses for a hundred miles above its mouth commencing at the falls, fifteen miles below where 
we struck it. The strata which compose its bed and banks have a distinct dip to the north- 
west, rising towards the southeast, where they have been upheaved in the elevation of the 
Mogollon mountains. 
Towards the southwest they also rise rapidly, forming the slope descended by our party. 
On the northeast they are nearly horizontal for a few miles, and then begin to rise toward the 
western spurs of the Rocky mountain system. From this description it will be seen that the 
Little Colorado occupies nearly the bottom of a synclinal trough or basin, of which the moun- 
tains I have enumerated form the rim of the southern half. 
The fall of the river in this part of its course is somewhat more rapid than the dip of the 
strata, so that, following it towards its sources, we were constantly ascending in the geological 
series. At the crossing we mounted a distinct step in the scale, formed by the red sandstone 
group. Fifty miles above this point, as I learn from the members of our party who followed 
the course of the stream around to Fort Defiance, the variegated marls which overlie the red 
sandstones close in upon them, and form the substratum of the remainder of their route to the 
fort. These, to us, new elements in the geological column exhibit the following characters: 
Red sandstone formation.—The limestone which forms the surface rock west of the Little 
Colorado has a dip even more rapid than the descent of the slope of the valley, and three miles 
from the river it passes beneath a red sandstone and disappears. This rock was first seen in 
tached outliers, left in the erosion of the general surface, often of most grotesque and 
om kable forms. The stratification of these buttes is concordant with that of the limestone, 
but along our line of observation the two formations are perfectly distinct, and we saw nothing 
ae he interstratification described by Mr. Marcou. This red sandstone forms part of a group 
of strata 
several hundred feet in thickness, which, though exhibiting considerable differences 
