Shingle on the East Coasts of Xeiv Zealand, 79 



able depths. It has been observed to do so to a limited 

 extent at as great depths as 6 and 8 fathoms. But whether 

 shingle is thrown up again from such depths on to the beach 

 is doubtful. 



(15.) These propositions need to be confirmed by further 

 information before they can be considered of general appli- 

 cation. 



59. This paper has extended to a much greater length than 

 the author anticipated, and is not so complete or satisfac- 

 torily arranged as he would have liked. He trusts, however, 

 that it may not be without interest to members. Much 

 remains to be learnt regarding the movements of shingle, 

 even in the cases dealt with in this paper. Observations 

 elsewhere require to be made before general conclusions can 

 be safely drawn. The author has, nevertheless, attempted 

 to generalise to some extent, in order that others may be the 

 better able to make use of what he has written ; for a bare 

 relation of facts of this nature is, as a rule, of very little 

 use unless the facts are connected and the principle under- 

 lying them explained in some way. The author trusts that 

 any errors into which he may have fallen will be pointed out, 

 and that some one else having opportunities of observing 

 the action of shingle will be induced to give some further 

 information on the subject. 



60. To facilitate the collection of information of an uniform 

 character, a few points which ought to be noted are 

 mentioned in the Appendix (e — p. 84). Such particulars 

 collected from different localities would be comparable and 

 would probably soon remove most of the difficulties which 

 now surround the subject. 



Note to Par. 55, regarding Wave-action at considerable 

 depths (see also par. 29 et seq.) : — 



On a rocky bottom, small stones and sand would be very 

 liable to be scooped out of crevices and hollows and forced 

 to rise to the surface by wave-action ; while a similar result 

 would not take place, at the same depth, on a homogeneous 

 bottom, which would yield equally in all directions. A 

 rocky bottom would reflect the waves. 



