ELISHA MITCHELL SCIENTIFIC S(3CIETY 



31 



the Neuse, and the Cape Fear run well back to the streams 

 lying to the northward. In the case of these streams the 

 dip of the strata is not such as to aid in the making of the 

 Such conditions are represented in Fig- 



right bank higher 



Fig VI. 



ure IV. In Figure V the arrangement of the strata is such 

 as to hinder rather than help the deflective effect of rota- 

 tion; and yet this is the structure of the Carolina region, as 

 shown in Figure VI, which is taken from Kerr.* But the 

 rocks here are imperfectly lithified, and so friable as to yield 

 readily to the influence. 



The Mississippi River does not act consistently through- 

 out its course, but in most instances its right bank is higher 

 except where the prevailing winds are from the north-w^est. 

 At Burlington, Iowa, the east or left side is low, and the 

 trains of the C. , B. & Q. Railroad reach the bridge over 

 embankments and trestle-work, but run directly into the 

 town on the high right bank of the river. x\t Dubuque 

 just the opposite conditions exist. 



Turning to regions south of the equator, we find in the 

 plains of Canterbury, New Zealand, the requisite condi- 

 tions. The Rakaia River cuts through Quaternary strata 

 and into late Tertiary, and its left bank is its steeper bank. 

 This is also shown in all the rivers entering Tasman Bay 

 through strata of the same age, and there are doubtless 

 many other cases in the same region. I have not at hand 

 the maps and geological report for that region. 



* Geology- of Xorth Carolina, Vol. I, 1875, p. 10. 



