162 EXPLORATION OF THE CANONS OF THE COLORADO. 
which head back in the plains and bad-lands, and cut across ridges and 
through mountains, are anaclinal, while those on the south side, which head 
near the summits of the mountains, and roll down to the foot of the range, 
and then turn off into the Green, are also cataclinal above, and monoclinal 
below. 
Taking the general course of Green River through the Uinta Mount 
ains, without regard to the several portions, as above mentioned, it would 
be described as diaclinal. 
The explanation of the canons of Green River will assist us in under 
standing the origin of the lateral valleys and canons. The streams were 
there before the mountains were made that is, the streams carved out the 
valleys, and left the mountains. The direction of the streams is indubitable 
evidence that the elevation of the fold was so slow as not to divert the 
streams, although the total amount of elevation was many thousands of feet. 
Had the fold been lifted more rapidly than the principal streams could have 
cut their channels, Green River would have been turned about it, and all 
the smaller streams and water-ways would have been cataclinal. 
Thus it is that the study of the structural characteristics of the valleys 
and canons teaches us, in no obscure way, the relation between the prog 
ress of upheaval and that of erosion and corrasion, showing that these 
latter were parl passu with the former, and that the agencies of nature pro 
duce great results results no less than the carving of a mountain range out 
of a much larger block lifted from beneath the sea; not by an extravagant 
and violent use of power, but by the slow agencies which may be observed 
generally throughout the world, still acting in the same slow, patient manner. 
There are yet some interesting facts to be observed concerning these 
inter-hog-back valleys. Their floors are usually lower than the general 
surface farther away from the mountains. There seem to be two causes for 
this. The great fold having been lifted and truncated prior to the exposure 
of the rocks farther away from the mountains, its strata present their edges, 
instead of their upper surfaces, to the down falling rain, and the softer beds 
are not so well shielded by the harder. Erosion hence progresses more 
rapidly than where the beds are approximately horizontal. 
Again, the mountains, with peaks among the clouds, condense their 
