82 



THE GEOLOGIST. 



with organic matter, and continually send forth young vigorous 

 shoots. To these may be added Triticum junceum, T. loUaceum, 

 Hordeum maritimum, Foa maritima, P. hulhosa, and RotthoJlia in- 

 cuynnfa, the last a beautiful and rather rare grass, which becomes 

 towards autumn of a deep yellow colour, gradually blending into 

 a bright crimson ; besides these are certain species of Sahola, Beta, 

 Galium, (fcc. among the dicotyledons which flourish upon the dunes or 

 near the sea, especially where there is mud as well as sand. To them 

 we must add two ligneous plants, which contribute more than any 

 others to fix the moyable sand of the dunes we speak of ; the one is 

 a stunted willow, Salix cinerea (or a variety), with ash-coloured leaves; 

 the other, a remarkable plant, called the Sea-buckthorn {Hippoplicea 

 rhamnoides), is a thorny shrub, some four or five feet high, bearing a 

 bright orange-coloured berry, like that of the holly. 



Some of these, and many other plants which we cannot mention 

 here,* might be cultivated with advantage on the sand-hills. Indeed, 

 such has long been my conviction, and in 1855 I intimated to the 

 Belgian Government that the cultivation of maize or Indian corn, for its 

 starch, in the more fertile parts of the dunes of Flanders, might meet 

 with success.t Some years ago I called attention J also to this fact, 

 that, if we consider a soil composed of pure clay, another of limestone 

 or chalk, and a third of sand, it will be found that of these three, the 

 one composed of pure sand is the most favourable to the development 

 of vegetables. But the sand of the Flemish dunes is not quite pure ; 

 it is mixed up with a considerable quantity of debris of shells, the 

 fragments of calcareous matter being reduced to the size of the gi-ains 

 of sand ; it reposes upon a sort of marl, — the well-known Argile grise 

 d'Ostende, which in some places lies bare upon the sea-shore ; so that 

 with a little trouble the moyable sand-hills might be converted into 

 a fixed and fertile soil, containing all the necessaiy elements, — sand, 

 carbonate of lime, clay, organic matter, salts, <fcc. Add to this the 

 purity of the maritime air, the presence of minute quantities of salt § 

 and iodide of sodium || in the sand, or, at least, this iodide is found in 

 the plants of the dunes, though some say it has never been discovered 

 in the sand on which they grow, and we shall not be so astonished at 

 the remarkable fertility which some of the more favoured spots of these 

 sand-hills present to us. 



* Amongst others a peeiihar species of "Old Man'j" {Artemisia maritima), 

 Sweet-briar, some species of SoJanum, Viola, Lotus, Linum, Daucus, &c. 



f See mv Memoire sur la Fecule et les substances qui peuvent la remplacer dans 

 rindustric' Bruxelles, 1855-6, J. B. Tircher. 



J Journal de la Societe des Sciences Medicales et Naturelles de Bruxelles, 

 Oct. 1854. 



§ On the uses of salt in agriculture, see an excellent prize essay by my friend 

 Dr. ]Max. De Saive, of Brussels, founder of the Veterinary School of Medicine 

 at Liege, entitled Memoire sur Ics usages du scl en Agricultmr,''' and to which the 

 Brussels Academy awarded their gold medal some years ago. — T. L, P. 



II A curious experiment was "made some time since by M. Blenguii, upon 

 the effects of iodine aiul bromine on vegetation. Some seeds were found to 

 germinate with astL'uishing rapidity if tliey were sprinkled over with a slight 

 quantity of a solution of iodine, or iodide of sodium, — T. L. P. 



