I9III STEVEXSOX— FORMATIOX OF COAL BEDS. 537 



that perhaps a quarter or perliaps a third of the sward was removed. The 

 furrowing in this pasture, by the way, represents the most extensive flood 

 removal of sward that I have ever seen. Now considering the translocation 

 of material generally by the flood, it is clear that despite the favora1)le con- 

 ditions due to abundant vegetation and to a higher declivity of the flood 

 than that of the normal stream, the ratio of organic matter moved to the 

 inorganic sediment was trifling. . . . What is true of that flood is, I am con- 

 vinced, true of river floods generally — while the flooded river generally has 

 its transportative capacity greatly increased, the material transported is chiefly 

 inorganic, so that the resulting sediments are mainly mud, silt or sand, rather 

 than organic accumulations." 



The writer rode through much of the area two months after the 

 flood had subsided. The chief evidence of great flood presented by 

 the vegetation consisted of somewhat inchned trees, deposits of 

 debris in branches of trees at a distance above the stream and an 

 occasional furrow in the sod. These furrows were produced wlien 

 the water in swirling around a projecting rock worked under the 

 sod and, soaking the materials below, burst the cover, so opening 

 the way for making a gully. In the forested portions, the litter 

 seemed to have suffered very little injtiry beyond, as noted by 

 McGee, receiving a cover of inorganic sediment. 



Murphy^"' has described a flood on Willow creek in Morrow 

 county, Oregon, a stream combining the features of a torrent with 

 those of a river. The creek, 30 to 40 feet wide and enclosed in 

 banks 10 to 15 feet high, has a fall of 38 feet jier mile, but, unlike 

 most of such streams, it flows through a fertile valley, 500 to 1.500 

 feet wide. The storm causing the flood of 1903 was brief, a cloud- 

 burst, and the flood had passed in less than an hour. The water 

 came down as a mass, 20 to 25 feet high, with a slope in front of 

 about 30 degrees, and it was 500 feet wide. It swept away a great 

 part of a town which was in its path. Xo details are given respect- 

 ing the damage done to vegetation, btit some incidental remarks make 

 the matter sufficiently clear. Referring to methods of determining 

 the high-water level of floods, he says that trees are the best marks ; 

 small trees are often bent over and silt or light drift is deposited on 

 them. When the water pressure is removed, the trees straighten up 



" E. C. Murphy. "Destructive Floods in the United States in ifX>3," 

 U. S. G. S. Water Sup. and Irr. Paper. 96, 1904. pp. Q-12. 



135 



