1885.] SAND-PLAINS OF BELGIUM. 273 



tions by projecting rocks or rocky ground, similar sand-beds, sand- 

 plains, and sometimes sand-dunes are found all along the coast 

 southward to the Bay of Biscay, and beyond it and northward and 

 eastward along the shores of the German Ocean, the Skagerrack, the 

 Cattegat, the Baltic, and tlie Gulf of Finland to St. Petersburg, and 

 onward to the far east, skirting the shores of the Black Sea and 

 the Caspian, and on still, losing themselves in Siberia, and 

 China, Bokhara, Turkestan, and India — extensively bound down by 

 vegetation of natural production, with here and there like results 

 produced by artificial plantation. 



Examined by the eye, sand is seen to consist chiefly of minute 

 particles of quartz, mixed sometimes with fragments of other 

 minerals, and not unfrequently containing an intermixture of frag- 

 ments of shells and other remains of animal and vegetable 

 structures, the quartz being the most constant and most character- 

 istic constituent. The composition of all sand is by no means the 

 same, and there is much involved in this. But at this stage the 

 statement which has been made may be accepted as a general state- 

 ment of very extensive application. The quartz which may be 

 considered the characteristic of all true sand is often angular, but 

 not unfrequently it is of a somewhat rounded shape. Crystallo- 

 graphists have shown that large crystals consist of small crystals, 

 and diamonds may be reduced in size by the dexterous application of 

 force to split them in a plane of fraction peculiar to each. So may 

 large quartz crystals. Though these statements do not meet all 

 the requirements of a profound study of sand-drifts, they may sufiBce 

 to warrant us to proceed to the inquiry. How have the con- 

 stituents of the sand been brought into the plains ? Though these 

 may be described generally as subterranean deposits, inland sand- 

 plains, and the sea-coast and sea-basin, the latter seems to be 

 generally recognised as the bed of the supply whence most of the 

 sand with which we are conversant has come. 



Sand has been associated with thoughts of the sea-shore, and the 

 sea-basin seems to be the immediate source of the sand of which 

 drifts are being formed along the coast-line ; for fast as it may be 

 drifted inland, new and apparently int(yminable supplies come up 

 from the deep, so that the sand on the sea-shore undergoes no 

 diminution, but seems rather to increase. It is true that we meet, 

 as has been intimated, with extensive plains of sand far from the 

 sea plains — measured not by miles, but by hundreds of miles, as are 

 the steppes of Eussia and the sand-plains of lands intermediate 

 between the Empire of Eussia and the Empire of India, the sand- 

 plains stretching from the shores of the German Ocean through 

 Northern Germany to St. Petersburg and beyond, and the sandy desert 



s 



