82 Shingle on the East Coasts of JS T eiv Zealand. 



slope from the wave immediately preceding," is understood by 

 the author to mean a meeting of the waves on the slope, in 

 which case the downward movement of material would 

 be arrested, and the cutting-out action consequently 

 prevented. Any shingle thrown up by the waves would 

 then remain on the beach. When c - the water descends 

 directly upon the pebbles, as is the case where the waves 

 break at comparatively long intervals," the return waves 

 are able to act with full effect, and, the slope being steep, 

 the destructive action goes on freely. 



(2.) Results of Observations by the Author 



(c.) Results Noted, (See par. 41.) 

 The author did not notice the different effects of off- 

 shore and on-shore winds, as above ; but the difference 

 resulting from waves corning obliquely on-shore, and from 

 those coming directly on-shore or striking the shore nearly 

 at right angles, was most marked, particularly near the 

 time of high-water, when the lower portion of the beach 

 would be submerged. 



Waves coming obliquely on-shore appeared to scoop out 

 the shingle, to throw back the beach, and to form a steep 

 slope with large shingle on it. These observations apply 

 more particularly to the upper part of the beach ; the lower 

 portion, when it could be observed, was usually flatter than 

 before. 



Waves coming directly on-shore, or striking the shore 

 nearly at right angles, appear to form a natter slope, to 

 widen the beach, and often to cover it with fine material, 

 which when wet appeared from a little distance like mud ; 

 but on close examination it was found to be coarse sand, 

 formed of material similar to that of the shingle. These 

 waves would draw down the shingle from the steep slope 

 formed by waves striking the shore obliquely, and raise the 

 lower part of the beach ; and further, as material is not 

 carried along the shore by these waves, fine shingle or 

 coarse sand thrown up on the lower and natter part of the 

 beach must remain there. 



(d.) Modifications of the above 'probably necessary under 

 certain conditions. 

 The author doubts whether the effect of waves striking 

 the shore, either obliquely or at right angles, would be 



