402 F. p. GULLIVER — CUSPATE FORELANDS. 



the initial coast or shallow bottom being deposited by the offshore 

 currents. * 



Sea Transportation. 



At a later stage, when the supply of waste has increased beyond the 

 power of the currents to immediately deposit it offshore, transportation 

 alongshore will become more important and the growth of forelands may 

 take place in certain places. The tendency of shore currents is undoubt- 

 edly to form curves in the shorehne which will be satisfactory to the par- 

 ticular current acting. In a general way the radius of curvature of the 

 shoreline will be proportional to the strength of tlie alongshore current. 



The writer makes the following distinction between the sea action upon 

 the inner t shoreline, which includes the more protected coasts of bays, 

 drowned valleys, sounds, channels, etcetera, and its action upon the outer f 

 shoreline, which is that of the exposed coasts of the ocean. The ocean 

 currents have little direct effect upon the inner shoreline, and the wind 

 has not opportunity to develop current eddies of large radius of curva- 

 ture upon inland waters. In these narrow arms of the sea the tidal cur- 

 rents are the preponderating force. The ocean current and the local wind 

 current must be of less importance here than the tidal currents. It may 

 be stated as a general princi[)le that the most effective agent of shore de- 

 velopment upon the inner shoreline of drowned topogra])hy is the tidal 

 current. Broad ba3^s form a middle ground where an}'' of the three forces 

 may be the strongest. Uj)on the outer shoreline the ocean eddy currents 

 are the most effective, while upon lakes and inland tideless seas the local 

 wind currents are the most important factor. 



Current Cusps. 



FORM. 



The four great capes along the eastern coast of the United States, 

 namely, Hatteras, Lookout, Fear, and Canaveral, are so well known and 

 have been so frequentl3Mna})ped that a general description is here unnec- 

 essar3^ The theory of current cusp formation Avill therefore first be con- 

 sidered and the more detailed facts of form introduced afterward. 



BACKSET EDDIES. 



The ocean circulation is made up of great eddies, which in turn set up 

 smaller eddies between the main current and the coastal border. These 



* For the method of wave attack, see Gilbert : Monograph I., U. S. Geological Survey, chap, ii, vfiih 

 references; Lyell: Principles of Geol., 11th ed., 1872, vol. i, chaps, xx-xxii ; Le Conte : Elements of 

 Geol., 2d e.l., 1882, pp. 31-43 ; Penck, loc. cit., vol. ii, pp. 4G0-497, with references. 



f See Penck, loc. cit., vol. ii, p. 551. 



