KROSION ON NORTH BRANCH OF THE ROUGE 



341 



had the water running close at its foot. Perhaps a third of this was 

 actively slipping and broken. The surface was uneasj'^ in all of it, but 

 two-thirds of it was such as was not counted at all before. 



Eight per cent of the course is bluff close to stream, 40 per cent of this 

 on the right and 60 of the left. The average length of a scaur on the 

 right is 170 paces; on the left, 180. Disorder takes the place of system; 

 flood-plain is gone; scaurs are gone. Steep bluffs are there in varying 

 percentage — now right, now left. 



The plain is a terrace beneath wliich tbe Kouge has incised its course. 

 The water is clearer than the lower Eouge, muddier than the middle 

 Rouge. The river does not cling to either bluff and its course is nearly 

 south. An interesting item revealed by the TJ. S. Geological Survey's 

 mapping is that tlie 600-foot contour is crossed by the lower Rouge 3 val- 



Blaffx cfoKC to Water on the North Braiicli of the Hoiiye 



Bluff 



paces. 







Miles. 







Right. 



Left. 





660 



550 



5.4 



80 



420 



4.4 



830 



1,400 



4.4 



370 



280 



2.8 



325 



775 



2.8 



620 







1.1 



2,885 



3,425 



20.9 



DirtTtioii. 



South-.southeast . . . . 



South 



Southeast 



South and southeast 



South 



South 



South 



Percentages 



of blufl' close 



to stream. 



(i 



•') 



13 



(i 



10 



13 



Percentages 

 of close bluff 

 to the right. 



54 



29 

 100 



40 



ley miles from Dearborn, where the streams unite, by the middle Rouge 

 5 valley miles, and by the JSTorth branch 8I/2 from the same point. The 

 surface of the country is near the same level at the three points, but the 

 North branch has only half or a third as much fall as the others, being 

 already cut to a much lower grade. It is not actively deepening its 

 course; neither is it cutting actively sidewise. 



Rattle Run 



This is a branch of Pine river, 60 miles northeast of the Rouge, near 

 Port Huron. A length of about three miles upstream from the mouth 

 was examined by a student of the author, Mr A. E. Parkins, now of the 

 Holland High School. The flow in this part of the stream is to the 

 uorth-northeasl:. It is typical open flood-plain, 5 per cent of its length 

 in scaur and another 10 per cent in active slip, but fairly grassed, 64 per 



