252 THE JOURNAL OF BOTAXT 



are able to root and continue growth in tlie new terrain {^e.g. shingle) 

 which invades and overlies the original habitat {e.g. salt-marsh). 

 Though the forces of wave-action are more violent than those of wind, 

 and shingle is less suitable for plant growth than sand, yet by the use 

 of proper methods it seems reasonable to expect that this combination 

 also will have to submit completely to the control of man. 



The chapters which follow — on " Tidal Land Reclamation " and 

 " Erosion and Accretion " — are again from the non-biological point of 

 view. Information is supplied in great detail concerning the planning, 

 building, and cost of sea-walls and groynes. A study of this portion 

 of the book by those who have to deal with foreshore problems should 

 save many thousands of pounds and prevent many failures, which in 

 the past have so often occurred solely because those responsible were 

 ignorant of the known results of experiment elsewhere. The refusal 

 to expend adequate national funds to meet the requirements of each 

 case is well stated to be a disgrace to the nation, especially when there is 

 so much wasted expenditure. It is clearly indicated that each of the 

 forces operative on the foreshore requires to be understood ; their par- 

 ticular action and resultant in each locality need expert study before 

 Avorks intended to withstand them ai'e entered upon. This part is 

 well illustrated, as is the book throughout, but the text is again 

 often badly written : e. g., "The broad standard rule for the level of 

 the sluice outfall may be stated as a level such that the drainage 

 can get away freely from about half -ebb to half-flood" (p. 132). A 

 " level " cannot be a " rule " : the meaning might have been made 

 clear in fewer words *' The .... rule is for the level .... to be such 

 that the drainage . . . ." It is a pity that so excellent a book should 

 be marred by indifference to clear expression. 



Mud flats and their vegetation are then described, and the way in 

 which plants raise the level of the flats to such a height that they can 

 be reclaimed (they apparently can never reclaim themselves) is 

 clearl}^ elucidated. The special case of Spartina is fully discussed, 

 with a warning of the danger that it may, unless prevented, cause the 

 silting-up of harbour channels. It is shown how the details of the 

 development of the successive stages on mud flats often depend upon 

 the historical factor, i. e. the introduction of a species at a critical 

 stage. As the exact functions of each species are more clearly under- 

 stood, owing to detailed ecological studies such as are carried out by 

 Mr. Carey's school at Blakeney, it bei'-omes increasingly possible to 

 control and hasten the development of an area by the deliberate 

 introduction of various plants at desired spots or periods. The 

 economic value of such ecological studies is ably demonstrated, and 

 foreshore owners may study vegetation to considerable profit. A 

 chapter on "Miscellanea" (Cliffs, River-banks, &c.) completes the 

 study of tidal areas in general. An interesting account of Bhikeney 

 Point shows how the existing structure and plant-covering is related 

 to the physical and ecological factors which produced it, and serves as 

 an illustration of the statements made earlier in the book. 



The remainder of the volume deals with problems of administra- 

 tion and control. The great evils attending the usual British method 

 of letting everybody " gae his ain gait" are well shown — that a 

 private individual should in 189G be able to wreck a permanent fore- 



