TIDAL HYPOTHESIS. 



413 



Where the initial slopes were less steep, less contrast is seen between the 

 oldland and the foreland. 



TIDAL HYPOTHESIS. 



Before considering other cusps which differ somewhat from West point, 

 let us look for a moment at what might be expected to result in narrow 

 channels with sides nearly parallel. Waves would attack this inner shore- 

 line to a greater or less extent at all points. When adolescence is reached 

 in the process of shore evolution and waste is supplied faster than it can 

 all be carried offshore, it will be transported and deposited somewhere. 

 What is the agent of transportation? Where should one expect to find 

 the waste deposited ? It has already been pointed out that the great sys- 

 tem of ocean eddy currents is not able to affect the inner as it does 

 the outer shoreline. Local 

 winds must produce small 

 currents proportional to 

 the size of the water bodies, 

 but these will be so weak in 

 narrow channels that their 

 effects will be lost in those 

 of even moderately strong 

 tidal currents. Thus it 

 seems safe to conclude that 

 the probable agent of trans- 

 portation in such channels figure ^.-Ideal Scheme" of tidal Inflo 



is the tidal ebb and fioAV. Washington. 



An ideal scheme of inflowing tide with the eddies which would prob- 

 ably accompany it is given in figure 7. Where the movement is least in 

 the triangles of more or less dead water between the several members of 

 the circulatory system the deposition would take place. In the majority 

 of places the outflowing tide would reverse the direction of flow and 

 transportation of shore waste ; therefore the combined action of ebb and 

 flow would shape the tidal foreland so that its central axis would be at 

 right angles to the general direction of tidal flow. 



The cuspate forelands which are mentioned under the three following 

 heads are arranged in three stages of progressive development, the V-bar 

 stage, the lagoon-marsh stage, and the filled stage. 



low^ Port Discovery^ 



V-BAR STAGE. 



A much younger stage than that of West point is seen on the same 

 sheet at Meadow point. Here the bars surround a relatively large lagoon 



