HYDROGRAPHY OF THE MARINE WATERS 55 



course of its journey, and largely dissipated. Wave attack expends its full 

 energy upon a bar which receives little material from the distant headland to 

 offset the ravages of marine erosion. Hence the bar is driven landward with 

 greater ease, and during its retreat the waves cut through first here, then 

 there, forming inlets which are not closed as readily as where debris is more 

 abundantly supplied. Far from headlands, therefore, there should be a tend- 

 ency for lagoons to be narrow and for bars to be broken by frequent inlets. 



" The Carolina coast is so complicated by the three cuspate bars forming 



Capes Hatteras, Lookout, and Fear that one might scarcely expect to find 

 the relationships characteristic of simple offshore bars. Yet if we compare 

 different sections of the coast in a broad way, ignoring local abnormalities, 

 we seem to see the working of the same laws controlling cases previously 

 discussed. The headland for this section is the margin of the coastal plain 

 of Virginia, south of Cape Henry, and the shore currents move in a general 

 north to south direction."* We may recognize four natural subdivisions of the 

 coast: a first section from the headland to Cape Hatteras, a second between 

 Capes Hatteras and Lookout, a third between Capes Lookout and Fear, and 

 a fourth between Cape Fear and a point just west of Little River, beyond 

 which the offshore bar seems to touch the mainland again. In the first section 

 the inlets number but 2 in a distance of 113 miles, and the lagoon attains a 

 great width with comparatively little filling. The abnormal width in parts of 

 the first two sections is probably due to an exceptionally gentle slope of the 

 sea-floor along the Cape Hatteras axis. In the second section of 72 miles, 

 there are three inlets, giving an average spacing of 4 to 100 miles, and the 

 lagoon becomes comparatively narrow toward Cape Lookout. In the third 

 section the number of inlets increases to 9 in 100 miles, while the lagoons 

 narrow still more and become much more filled with marsh deposits. At Cape 

 Fear the lagoon broadens out considerably, but the width here is only seven 

 and one-half miles as compared to twelve and one-half at Cape Lookout, or 

 thirty miles at Cape Hatteras. In the fourth section there are eight inlets in 

 40 miles, which is equivalent to a spacing of 20 inlets to 100 miles; the bar is 

 driven back nearly to the mainland, and the narrow lagoon is almost com- 

 pletely filled with marsh. Despite its complexities the Carolina case appears 

 to meet the requirements of the theory." "^ 



24. The basis for this statement on current direction is not given, although Prof. Arthur N. 

 Strahler, who worked with Dr. Johnson for some years, has informed me he believes the current 

 direction was inferred from the shape of the inlet mouths. It is interesting to note that such a 

 direction is compatible with Abbe's theory ; yet, as already mentioned in the section on Circulation 

 Offshore, Johnson (1938) discussed the formation of the cuspate Carolina capes on the basis of 

 geological relationships having no bearing on Abbe's hypothesis. 



25. The Corps of Engineers (1948) gives the following up-to-date account of inlet distribu- 

 tion: "The prevalence of inlets increases to the southward along the coast. The latest informa- 

 tion indicates that there is only i inlet open along the 100 miles of coast from the Virginia line 

 to Cape Hatteras, 6 in the second hundred miles, 12 in the third hundred miles, and 6 between 

 the Cape Fear River and the South Carolina line, a distance of 32 miles." 



