CHAPTER IX, 
GEOLOGY OF THE ROUTE FROM FORT DEFIANCE TO SANTA FE. 
GENERAL FEATURES.—F orT DEFIANCE. —STRUCTURE OF VALLEY CANONCITA BONITA.— TRAP BUTTES.— GARNETS AND BERYLS.— DISTURBED 
CRETACEOUS ROCKS EAST OF FORT DEFIANCE. —CRETACEOUS LIGNITES.—SCORIA FORMED BY THEIR COMBUSTION.—DISLOCATED STRATA 
AT SALT SPRING.—CAMPBELL’S PAsSS.—MOUNT TAYLOR.—VOLCANIC PHENOMENA SIMILAR TO THOSE OF SAN FRANCISCO MOUNTAIN. — 
SECTION OF STRATA AT AGUA AzUL.—C. CRETACEOUS SANDSTONES OF COVERO AND LAGUNA.—SECTION AT 
LAGUNA.—RED SANDSTONES AND GYPSUM.—CRETACEOUS ROCKS ON THE PUERCO.—STRUCTURE OF THE RIO GRANDE VALLEY.—SANDIA 
MOUNTAIN.—ALBUQUERQUE TO SANTA FE.—SECTION ON GALISTEO CREEK.—UPPER CRETACEOUS FOSSILS FROM NEAR GALISTEO.—TRAP 
DYKES NORTH OF GALISTEO CREEK.— TRAP PLATEAU.—THE CERILLOS.—CHALCHUITL.—STRUCTURE AND RELATIONS OF THE SANTA FE 
MOUNTAINS.—CARBONIFEROUS LIMESTONE.— JURASSIC AND TRIASSIC ROCKS OF MR. MARCOU. 
FORT DEFIANCE. 
The geology of the region lying between Fort Defiance and the Rio Grande, while including 
only the rocks that have been so fully described in the preceding chapter, presents many new 
features in the condition in which they are found. Inthe Moqui country all the strata interven- 
ing between the Carboniferous and the Upper Cretaceous are nearly horizontal, and nowhere 
dislocated or disturbed, each member of the series in the beautiful exposures which came under 
our observation holding its proper relative position, and exhibiting its normal aspect. ast of 
ort Defiance, on the contrary, the table-lands, although continuous with, and once in all 
respects similar to those we before passed over, have been broken up by various lines of dislo- 
cation of the Rocky mountain system, and their strata thrown about in the greatest confusion. 
The difficulties which geological investigations here present are such that it would be scarcely 
possible for one who had not studied the formations here represented in some other school to 
arrive at conclusions of unquestionable accuracy. Coming, as we did, to the examination of 
the complex structure of this disturbed region from one whose perfect quiet and magnificent 
sections gave us the best possible preparation for the task, we were, perhaps, able to accomplish 
as much in the solution of its problems as could be done by a party moving as rapidly as we did. 
Fort Defiance is situated in a picturesque valley of erosion not unlike, in its general aspects, 
to those lying west of it, yet exhibiting some peculiarities, both in the elements composing its 
geology, and their arrangement. It has been excavated in a north and south direction on the 
slope of strata dipping rapidly eastward from the summit of the anticlinal axis a few miles 
west of it. These strata have been cut through nearly to the Garboniferous limestone, while 
the cliffs bounding the valley on the east include about a thousand feet of Cretaceous rocks. In 
the midst of the valley several large castellated buttes of basaltic trap rise abruptly from its 
alluvial surface, the unyielding material of which they are composed having resisted the action 
of the agent that has removed the sedimentary rocks for miles around them. The structure of 
this valley will be most readily understood by reference to the accompanying wood-cut, which 
gives a transverse section of it. 
Tt will be seen from this section that the softer portion of the variegated marls forms thé 
base of the eastern boundary of the valley, and there is little doubt that its excavation has 
_ been effected in the same manner as that of the valley of the Little Colorado, viz: by the 
washing away of the softer strata on which the eroding stream has constantly had its bed, and 
the gradual descent of that stream along the slope of the surface of the harder rocks below, 
