4 
DAVIS: THE GRAND CANYON OF THE COLORADO. ap 
Dutton maintained the antecedent origin of the Colorado drainage sys- 
tem, trunk and branch. It is very probable that these geologists might 
now modify in some degree the statements that they made thirty and 
twenty years ago as to the indifference of the streams, especially of the 
smaller streams, to the displacements of the plateau region. Other 
origins may be suggested for several of these waterways. 
The Smaller Streams of the Grand Canyon District. — Cataract creek 
(called Cascade river by Newberry, pp. 62, 66, and Coanini creek by 
Powell, a, p. 197) follows in a general way the gentle northward dip of 
the strata that it dissects, and may well be classified as a consequent 
stream, revived with every uplift. A possibly consequent origin for 
that part of Virgin river which passes between the two parts of the 
Hurricane fault has been suggested above. The Little Colorado fol- 
lows a monoclinal belt of relatively weak Permian and lower Triassic 
strata for a hundred miles, and in this part of its course it may be 
plausibly regarded as a subsequent stream ; such was certainly its habit 
where we crossed it in the Permian belt on the Flagstaff-Tuba road ; 
but for forty miles northwest from this point to its junction with the 
larger river, it runs obliquely against the gentle structural slope of the 
Marble platform and enters the main canyon just east of the Kaibab 
monoclines, a highly significant fact which will be referred to further 
on. Paria creek has, according to the geological maps of the district 
(Dutton, ce, Atlas, sheets II., XXI., XXII.), an anticlinal course in its 
upper, and a monoclinal course in its lower part. Although the lower 
part is now deeply incised in resistant Triassic strata on the northeast 
border of the Paria plateau, its position there may have been gained by 
headward growth along the once-overlying weak strata of the gently 
dipping monocline during a lower stand of the land; for the stream 
seems to be accordant with the strike of the beds. The upper part of 
the Paria drains the denuded district in which the Kaibab arch fades 
away to the north (Dutton, a, pp. 253, 297); the lateral branches of 
the stream are here to all appearances normal obsequent streams, 
whose length increased as the denuded area widened ; the trunk stream 
is merely the axial member of the obsequent group, longer than the 
laterals because the dip of the strata to the north is gentler than to the 
east and west. The whole length of the creek may therefore be reason- 
ably explained as an example of spontaneous adjustment of drainage to 
structure, and not as of antecedent origin. House-rock valley is un- 
questionably subsequent, as has been implied already on page 124, and 
as will be more fully considered below. Kanab creek has every appear- 
VOL, XXXVIII. — NO. 4 4 
