1SV3.] J-«'J- [Kerr. 



observation was also very soon verified as to its general application. 

 Pursuing the subject, it was soon noticed that, as a consequence of this 

 topographical structure, the great roads as well as the towns and 

 residences on these streams are located very generally on the same side, 

 as may be seen by a glance at the map of the State. Another curious 

 point may also be noted here ; each of these rivers, between the point 

 where it enters the champaign and its mouth, makes a gradual sweep 

 towards the south (some of them more than one) ; so that they consist of 

 one or more curves, whose convexity is turned southward, presenting 

 the appearance on the map of a succession of catenaries hung between 

 two or more fixed points. A cross section of these interfluvial zones 

 will present about the followiug appearance : 



Ideal section across the Roanoke, Tin, Neuse and Cape Fear Rivers ; 

 d, Cretaceous; c, Eocene; b, Miocene; a, Quaternary. 



In seeking an explanation of this peculiar topography, the theory of a 

 gradual subsidence towards the south was first considered. The ob- 

 jections to it however were obvious and insuperable. Finding the same 

 observation to hold for the corresponding region of South Carolina, I 

 consulted the Geological Report of Prof. Tuomey. He had noted the 

 facts and their persistence through more than one State, but had rested 

 in the theory of an unequal subsidence. The sufficient objection to this 

 explanation is that there is no evidence of such a subsidence, but much 

 evidence that it could not have taken place without producing a very 

 observable difference in the present horizon of the formations affected. 

 And furthermore, the phenomenon is not confined to the superficial 

 •strata of the Quaternary or Tertiary formations. If the covering of these 

 were removed, a section of the Cretaceous would present the same 

 appearance. The cause, therefore, whatever it be, has acted over a very 

 large territory through a very long period. That cause is doubtless the 

 rotation of the earth, coacting with the force of the river currents. 

 Without stopping to refer to familiar instances of the sensible operation 

 of this cosmieal force in modifying the motions of projectiles, it is suf- 

 ficient to refer to the well-known law of motions developed by Prof. AV. 

 Ferrei in the Mathematical Monthly, vol. i. p. 307, according to which, 

 "In whatever direction a body moves on the surface of the earth there 

 is a force arising from the earth's rotation which deflects it to the right 

 in the noithern hemisphere, but to the left in the southern." 



To the obvious objection that the deflective force of the river current 

 is too inconsiderable to produce such effects, the equally obvious answer 



