CURRENT CUSPATE FORELANDS. 



407 



what the form there shown tells us of the history of their formation. 

 These charts cover such a large area and are executed in such detail that 

 it is impossible to reproduce them satisfactorily for the purposes of this 

 paper. The Coast Survey charts are accessible to many, and the facts 

 which are here ta.ken from them will be much better apprehended with 

 the charts in hand. 



In figure 4 is given atypical drawing of a current cuspate foreland. 

 In it are combined those features of the three Carolina capes and cape 

 Canaveral which the author deems impor- 

 tant to show the method of growth. Former 

 positions of the shorelines are indicated by 

 the ridges of dunes built by the wind along 

 the shore. Such former positions are beau- 

 tifully indicated in Canaveral (C. S., 160, 

 161), where three or four successive posi- 

 tions of the outline of the cusp, each further 

 to the left than the preceding, are delineated, 

 besides many lines of aggradation in each 

 position. Similar lines of growth are seen 

 at cape Fear where the present right shore- 

 line cuts off the eastern ends of the four 

 dune ridges extending east-southeast from 

 the light-house and curving sympathetic- 

 ally with the left shoreline. Cape San Bias, 

 on the west coast of Florida (C. S., 183, 184), 

 shows four stages on the right side and nine 

 successive stages of aggradation on the left 

 side. A more striking example of aggrada- 

 tion lines is seen in the cusp of Darsser 

 cape in the Baltic (Germ., 61, 62, 63), where 

 thirty-eight systematic and successive shore- 

 lines are indicated by dune ridges. 



The three criteria of form, offset, overlap, and stream deflection, by 

 which we may recognize the direction of dominant movement along- 

 shore are all seen along the Carolina coast, and are shown in the type 

 drawing (figure 4). To make the point clearer each of the criteria will 

 be considered separately and occurrences pointed out. The typical 

 hooked spit and the shoals will be considered under later headings. 



FiGURK 4. — Type current Cuspate 

 Foreland. 



OFFSETS IN THE CAROLINAS. 



Along the Carolina coast examples are numerous in which the right 

 shore curve offsets the left. Among these the following cases will be 



XLVIII— Bull. Geol. Soc. Am., Vol. 7, 1895. 



