explaiD.ed better by the so-called "material-moving povirer",, which will 

 be discussed later* At headlands this "power" will usually move in such 

 a dlrestion that the coast material will be moved avray from the point 

 to both sides o A typical example is the headland near R0nne on 

 Bornholmi, where the harbor is completely free of sand in spite of the 

 fact that there is sand on both sides o (Figures 7 and 8). furthermore.. 

 w"e must take into consideration tts strong undertows which occur on 

 steep coasts when sea gales are blowing. This undertow is partly the 

 result of the wind and partly of the seaward bottom flow of the water 

 which the waves have piled up. If the wind approaches land at a 90 

 degree angle, this undertow can be so strong that it can drag heavy 

 naterial with it „ 



Y/hen W, Gornaglia states that material is deposited on flat coasts 

 and eroded from steep coasts one can answer that flat coasts are flat 

 because deposits are being made, and that steep coasts are steep 

 because material is being eroded. This means that reason and result 

 can change place Sj and then the whole thing seems more reasonable « 



If the direction of travel of the waves is oblique to a steep 

 coast, the sand will most lively be moved away by the coastal currentSj, 

 while gravel and small stones, which are too Ybr-vij to be moved by 

 the currents, are left behind. Therefore, the presence of stones and 

 re sand^, or the absence of loose coast material , shows that the coast 

 is steep. One inust here keep in mind that the w^aves are strongest 

 on steep coasts and consequently here they are capable of handling 

 heavier material* When land winds are blowing, the undertow will move 

 landwardj and as a result, quantities of sand will be deposited on the 

 coast. On flat coasts the bottom tows are not so important and con- 

 sequentlyj the sand which has been moved to the coast by the waves 

 either will be deposited here or moved along the coast. 



It may be concluded from the foregoing that on coasts with a very 

 small difference in tide, the material drift occurs almost exclusively 

 as a result of the power of the viraves. Wave attack on the bottom 

 starts at the depth the bottom first reaches the movement of the waveo 

 This defines the seaward limit of the belt or zone inside which 

 material movement occurs. The zone will be broader as the coast is 

 more flat,, as tte stronger is the action of the wave, and as the finer 

 asd more easy to move is tbs bottom material. 



Professor Jfeinch-Petersen describes the influence of the vraves on 

 a sloping bottom as follows » When the waves break, the bottom material 

 will be disturbed and moved along the coast, partly by the wave 

 current, and partly, together with v.rhat is pushed forvrard along the 

 bottom., by the wave. The dirsction of the latter is determined by 

 th?5 90 degrees angle obliquity of approach of the wave, the obliquity 

 being determined by tfce wind. One can get a good picture of the 

 ii-g5terial movement if one looks upon the wave as an excavating machine 

 and the wav-B cuiTent as a conveyor belt which moves the material 

 which the excavating machine has loosened. Y/hen the machine (the 

 wave) reaches the shor® , it throws the material in a mojre or less 



