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



limit of the displaced mass. It also contains much more fine material 

 and is more or less wooded. At the lower limit, however, this rock slide 

 develops well defined rock stream features. It comes into the valley 

 from the south side, making a graceful curve where it joins the larger 

 north stream and follows down the left or south side of the valley, being 

 quite distinct from and yet parallel with the stream from the north branch, 

 until it finally ends 200 or 300 feet sooner than the north stream. In 

 plate 48, figures 1 and 2, the source of the material of the south branch 

 may be seen in the landslide that came down between the points marked 

 by the letters a and h. Likewise in plate 51, figure 2, may be seen to the 

 left of the letter a the scar of the landslide at the head of the north 

 branch, and to the right of a the source of part of the south branch. 

 This plate also shows the parallel ridges and troughs of the south branch 

 with their curving lines just as they unite with the north branch. The 

 trenches here shown are not to any degree due to water erosion, but purely 

 to the motion of the rock stream itself. 



In plate 52, figure 1, is to be seen the continuation of the above de- 

 scribed plate 51, figure 2, taken some 200 or 300 feet lower down stream. 

 The left part of the view shows a part of the north branch, the material 

 of which lies at a slightly higher level. The lower lying portion to the 

 right and in the center of the view represents the south branch flowing 

 in on a curve from the right. Finally plate 52, figure 2, shows the same 

 two fiows taken still farther down stream. The rock material from the 

 north branch continues still at a higher level and forms a bench of flat 

 lying fragments, while the material from the south branch stands at a 

 lower level and has its individual fragments turned on edge. This dif- 

 ference of level in the two branches continues to the end of the stream. 

 Here again we see a marked resemblance between this rock stream and a 

 glacier. In each case the materials from different sources and from 

 different tributaries travel down the stream without mingling. If it 

 were not for the fact that the rock material of the two tributaries is 

 exactly alike in appearance, this feature would l)e mucli more marked 

 than it is. 



It is an interesting fact that where tlie two streams come together and 

 are apparently squeezed into a narrow space between the steep sides of 

 the valley, there the evidences of motion are strongest, and there, too, the 

 rock fragments show most marked tendency to stand on edge. 



EocK Streams and glacial Action 



Eock streams as described by Cross and Howe in the San Juan Moun- 

 tains of Colorado are limited to the very high mountain regions above 



