Rivers of Northern New Jersey. 105 
This appears to me an unproved conclusion, and the eyvi- 
dence of it needs careful attention. It appears that there are 
several streams which descend from the crest of the mountains 
towards the flanks, but instead of running all the way out to the 
margin of the fold, they turn along the strike of a monoclinal 
valley, and thus reach the main river by a short cut. Such 
streams are cataclinal for a time, then monoclinal. It is in refer- 
ence to these that it is said, “the streams were there before the 
mountains were made;” and again that “the dramage was estab- 
lished antecedent to the corrugation or displacement of the beds 
by faulting and folding” (163). In approaching this conclusion, 
Powell says these streams cannot be consequent; for “valleys 
consequent upon the corrugation, which was one of the conditions 
of the origin of the Uinta mountains, could not have taken the 
direction observed in this system; they would have all been 
eataclinal, as they ran down from the mountains, and turned into 
synclinal valleys at the foot, forming a very different system 
from that which now obtains” (166). Nor can the streams be 
superimposed, for the “later sedimentary beds, both to the north 
and south, were found not to have been continuous over the 
mountain system, but to have been deposited in waters whose 
shores were limited by the lower reaches of the range” (166). 
Therefore the discordant streams must be antecedent. 
It appears to me that the possibility of error in this argument 
lies in the omission of all consideration of the migration of divides 
and the resulting adjustment of stream courses to deep internal 
structure ; but at the time of the exploration of the Colorado 
river, this important process in the development of rivers was not 
understood. It now seems only natural that the original, conse- 
quent, cataclinal streams, flowing down the slopes of the range 
from crest to flanks, should have permitted the opening of subse- 
quent monoclinal branches on the soft beds that they discovered ; 
and that the shifting of divides in these monoclinal valleys should 
have led to the capture of several cataclinal streams by that par- 
ticular one of the subsequent branches that grew out from the 
master stream, the Green river itself. Thus it must happen that 
the streams “which head near the summit of the range, and, 
running down the flank, turn into the Green river, are, in their 
upper courses, cataclinal, and when they turn to follow the strike 
of the rocks into Green river, are monoclinal” (161) : this being 
a normal result of river work in cutting down the thousands of 
