SEED AND ROOT 



185 



Pholoby-] 



FIG. 237. SAND-DUNE ON THE SUSSEX COAST. 



IE. Step. 



This photograph, taken from the landward side, shows how the Marram (Psamma arenaria) holds the loose sand 

 together. The wind scoops out hollows in the surface where unprotected by this grass ; but the immense bank as a 

 whole keeps its form and its protective power, owing to the network of underground stems and roots which prevent 

 any serious shifting, whilst the tough aerial stalks intercept much of the sand that would otherwise blow away. 



the encroachments of shifting sands have been extensively employed 

 for many years ; and the method has been greatly improved upon and 

 developed. 



So far back as 1780, M. Bremontier, an eminent French engineer, devised 

 the means (first suggested, it is said, by a priest of Mimizon) of fixing the 

 dunes. The practical value of his theories, which were adopted by the 

 Government, has been fully established by the experience of a century. An 

 American savant, Mr. G. B. Emerson, bears this testimony : - 1 1 visited, in 

 1872, the region saved by Bremontier, and examined the work he had done, 

 and its effects. The whole country, for more than a hundred miles along 

 the Atlantic coast of Gascony and from four to eighteen>landward, had been 

 covered with sand-hills. . . . The process of ruin had been going on for 

 centuries, and some of the sand-hills were hundreds of feet high. In the 

 midst of this recovered region I stopped a day or two at a beautiful town, 

 where a hundred thousand persons from Paris and other cities of France, 

 attracted by the genial climate and the health-giving atmosphere of the pine 

 forests, had passed the winter. I walked and drove along the sandy roads, 



