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Show 160 EXPLORATION OF 'rBE CA:RONS OF THE QOLORADO. edges of the strata, and run in a general direction with the dip of the strata until they reach the long valleys between hog-backs, then down these valleys they turn, sometimes cutting through intervening ridges, until they find their way into the Green, where they are turned to the south, away fi·om the mountain. It will thus be seen that the relation of the direction of the streams to the dip of the rocks is very complex, and, for convenience of description, I have elsewhere classified these valleys, on the basis of these relation!, in the following manner: Order first. Transverse valleys, having a direction at right angles to the strike. Order second. Longitudinal valleys, having a direction the same as the strike. Of the first order, three varieties are noticed: a, diaclinal, those which pass through a fold. (Fig. 53.) b, cataclinal, valleys that run in the direction of the dip. c, anaclinal, valleys that run against the dip of the beds. Of the second order, we have, also, three varieties: (Fig. 54.) (Fig. 57.) .A, anticlinal valleys, which follow anticlinal axe~. (Fig. 55.) B, synclinal valleys, which follow synclinal axes. (Fig. 56.) 0, monoclinal valleys, which run in the direction of the strike between the axes of the fold-one side of the valley formed of the summits of the beds, the other composed of the cut edges of the formation. (Fig. 58.) 1\Iany of the valleys are thus simple in their relations to the folds; but, as we may have two systems of displacements, a valley may belong to one class, in relation to one fold, and to another in its relation to a second. Such we designate as complex valleys. Again, a valley may belong to one class in one part of its course and to another elsewhere in its course. Such we designate as compound valleys. It will be further noticed that valleys may have many branches, but, in relegating a valley to its class, we consider only the stem of the valley proper, and not its branches. A great diversity in the features of all these valleys is observed. Most of these modifications are due to three principal causes: First, a great0r or ~Figure 63.·-A Diaclinal Valley. Figure M.-A Ca.Laclinal Valley. |
