662 MARIUS R. CAMPBELL 



their head branches directly toward the axis. This produced 

 ver}^ unsymmetrical basins in which the trunk streams are flow- 

 ing on the lower side of the basins, with the minor branches 

 reaching toward the stream next above. 



Sometimes these long aggressive tributaries work through 

 the divide and tap the headwaters of the stream next above. In 

 Fig. 1 1 there are two such cases of robbing ; one at the point E 

 where the branch D E has apparently cut through the divide c d 

 and beheaded the stream A B F G, and the other at the point / 

 where 7/ /has robbed A D I J oi the portion I J. 



(2) EFFECT OF THE EARTh's ROTATION ON DRAINAGE LINES. 



Kerr ^ observed such an arrangement of the streams of east- 

 ern North Carolina, but he attributed their origin to an entirely 

 different cause, viz., the rotation of the earth on its axis. In 

 arriving at this conclusion, he considered the possibility of a 

 tilted surface, but dismissed the idea as untenable. In support 

 of the former hypothesis he cited a few isolated cases which seem 

 to favor his view of the case. 



Gilbert,^ in his study of the effect of rotation, reached the 

 conclusion that the cause is adequate, under favorable conditions, 

 to produce such results, and referred to the drainage of the 

 southern side of Long Island as an illustration of the working 

 of the law. 



It is not the purpose of the writer to enter into a discussion 

 of the efficiency of the rotation of the earth in producing drainage 

 modifications of a certain type ; but rather to show that such 

 peculiarities are of very common occurrence in places where 

 rotation could hardly have been an active agent, and that some 

 other cause is capable of producing the same effect. As will be 

 pointed out later, changes of just such a character as those 

 described by Kerr in North Carolina and by Gilbert in Long 

 Island can be found in almost every stream of the Appalachian 



' Geology of North Carolina, 1875, by W. C. Kerr, pp. 9-12. 

 ^The Sufficiency of Terrestrial Rotation for the Deflection of Streams. Am. Jour. 

 Sci., Vol. XXVII, pp. 427-432. 



