670 H. B. PATTON ROCK STREAMS OF VETA PEAK, COLORADO 



level of 50 feet above the level of the side valley. This is shown in 

 plate 50, figure 1. This view is taken from the bottom of the side valley 

 looking up at the rock stream whose direction of motion is at right angles 

 to the line of view. 



DETAILS OF STRUCTURE 



Eeference has already been made to the ridges and intervening troughs. 

 The former are often merely long, narrow flats raised 4 or 5 feet above 

 each other, with no marked trench or trough between them. The rocks 

 composing these flat ridges usually have a distinct and often very marked 

 horizontal arrangement, the individual slabs lying flat. On the other 

 hand, in the troughs, especially where sharp and narrow, the rocks show 

 a strong tendency to stand on edge, with their long diameters parallel' to 

 the direction of flow. In plate 50, figure 2, is shown a mass of flatfish 

 rock fragments measuring from 1 to 3 feet in greatest length and turned 

 on edge. This view is taken at the bottom of a pronounced trough. 

 The contrast between the flat-lying slabs of the ridges and those turned 

 on edge is also brought out clearly in plate 52, figure 2. In this case 

 there is no real trough in evidence, but merely a higher bench of flat- 

 lying slabs and a parallel running lower bench in which the fragments 

 are mostly turned up on edge. 



It is also to be noted that where two flat ridges or parallel benches 

 occur on different levels there is usually a marked difference in the aver- 

 age size of the rock fragments composing the two benches. This differ- 

 ence in size persists throughout the whole length of the ridge. It can 

 hardly be explained except on the assumption that the material of the 

 two ridges comes from different sources somewhat after the manner of 

 two lateral moraines uniting to form a medial moraine. This contrast 

 in size of the constituent fragments may be seen in plate 51, figure 1 ; 

 likewise in plate 49, figure 2. 



The North Branch 



As above stated, this branch forms the major part of the whole rock 

 stream. It not only is much longer than the south branch, but after the 

 two streams unite the material from the north branch forms perhaps 

 nine-tenths of the entire mass and continues also farther down stream. 

 Throughout its entire length it is almost entirely free from fine material, 

 and also free from vegetation. This rock stream started at the point 

 a in plate 48, figures 1 and 2, in the shape of a regular landslide with an 

 initial direction of north 60 degrees west. Descending with terrific 

 velocity for some 1,200 or 1,500 feet vertically, the rockmass met with 



