GULLIVER. SHORELINE TOPOGRAPHY. 183 



In small water bodies, lakes and seas nearly without tides, the winds would 

 cause waves which in turn would originate currents of smaller radius of curvature, 

 which should produce smaller cuspate forelands. The cuspate points in the Danish 

 waters are probabl}' such forelands. Tliese are seen on the topographic maps of 

 Denmark in the following localities : Roskilde fjord (Denni., Hilderod), Suen Mel- 

 lem Smalandene (Denm., Saxkjobing, Vordingborg), Limfjorden (Denm., Logstiir), 

 on Langeland and the islands to the west (Denm., Svendborg, Nakskav, Gulstav, 

 Faaborg), and in other localities along the Danish and German coasts. 



The Bonneville cuspate forelands are proportional to the currents which existed 

 on the old lake and are similar in size and outline to the Danish cusps. Professor 

 Russell also reports V-bars upon the fossil shores of lake Lahontan.* These 

 cusps seem to have been built upward as the waters of the lakes rose, but the 

 water level never remained constant long enough for the lagoons to have become 

 filled, forming solid forelands, since Mr. Gilbert reports only a partial silting up.t 



6. Offshore Bar. 



Shelving Shore. — When the sea takes a new position of attack after 

 elevation, if the shore is shelving, wave-base intersects the smooth bottom 

 at some distance from the simple new shoreline, and the point of maxi- 

 mum wave abrasion is out from the coast at some point on the shelving 

 shore. This condition would obtain in the ideal case assumed in Part I. 

 From the forms of observed shores which slope gently beneath the water, 

 the action of the sea appears to be somewhat as follows. The waves at 

 first beat upon the coast and cut a faint cliff or nip. The point of maxi- 

 mum wave action is offshore, and there the waves heap up sand from the 

 bottom and a bar is formed alongshore. The waves abrade rapidly until 

 the offshore bottom to seaward of the bar approaches wave-base. Dur- 

 ing this deepening the waves have broken farther and farther offshore, 

 so that the bar has gradually moved seaward. When now the bottom to 

 seaward of the bar has been abraded almost to wave-base, a condition of 

 shore-grade is reached : the sea is able to transport and build into the con- 

 tinental delta whatever waste is supplied from the bottom and offshore 

 bar. As soon as material is taken from the bar it will retreat toward 

 the land. 



Stages. — The period of upbuilding and seaward growth of the offshore 

 bar has been regarded as the youth of the shoreline, and the period of 

 cutting back as adolescence, since the latter is a graded condition. Dur- 

 ing youth the seaward growth of the bar leaves long marshy strips, or 

 '' slashes," between the successive dune ridges formed along the shoreline. 

 These become overgrown with bushes, peat, etc. The lagoon behind the 



* Mon. XI., U. S. G. S., 93. 



t Lake Bonneville, 121, PI. XVIII. 



