528 SAKD CAERIED DOWN TO THE SEA. 



to be a product of the " great Kortli German drift," deposited 

 where they now lie before the commencement of the present 

 geological period, and he maintains similar opinions with regard 

 to the sands thrown up by the Mediterranean at the mouths of 

 the Nile and on the Barbary coast.* 



Sa/nd now ca/rried to the Sea. 



There are, however, cases where mountain streams still bear 

 to the sea perhaps relatively small, but certainly absolutely 

 large, amounts of disintegrated rock.f The quantity of sand 



* De Bodem van Nederland, i., p. 339, 



f The conditions favorable to the production of sand from disintegrated 

 rock, by causes now in action, are perhaps nowhere more perfectly realized 

 than in the Sinaitic Peninsula. The mountains are steep and lofty, unpro- 

 tected by vegetation or even by a coating of earth, and the rocks which com- 

 pose them are in a shattered and fragmentary condition. They are furrowed 

 by deep and precipitous ravines, with beds sufficiently inclined for the rapid 

 flow of water, and generally without basins in which the larger blocks of stone 

 rolled by the torrents can be dropped and left in repose; there are severe 

 frosts and much snow on the higher summits and ridges, and the winter rains 

 are abundant and heavy. The mountains are principally of igneous formation, 

 but many of the less elevated peaks are capped with sandstone, and on the 

 eastern slope of the peninsula you may sometimes see, at a single glance, 

 several lofty pyramids of granite, separated by considerable intervals, and all 

 surmounted by horizontally stratified deposits of sandstone often only a few 

 yards square, which correspond to each other in height, are evidently contem- 

 poraneous in origin, and were once connected in continuous beds. The degra- 

 dation of the rock on which this formation rests is constantly bringing down 

 masses of it, and mingling them with the basaltic, porphyritic, granitic and cal- 

 careous fragments which the torrents caiTy down to the valleys, and, through 

 them, in a state of greater or less disintegration to the sea. The quantity of 

 sand annually washed into the Red Sea by the larger torrents of the Lesser 

 Peninsula, is probably at least equal to that contributed to the ocean by any 

 streams draining basins of no greater extent. Absolutely considered, then, the 

 mass may be said to be large, but it is apparently very smaU as compared with 

 the sand thrown up by the German Ocean and the Atlantic on the coasts of 

 Denmark and of France. There are, indeed, in Arabia Petrsea, many torrents 

 with very short courses, for the sea-waves in many parts of the peninsular 

 coast wash the base of the mountains. In these cases the debris of the rocks 

 do not reach the sea in a sufficiently comminuted condition to be entitled to 

 the appellation of sand, or even in the form of well-rounded pebbles. The 

 fragments retain their angular shape, and, at some points on the coast, they 

 become cemented together by lime or other binding substances held in solu- 

 tion or mechanical suspension in the sea- water, and are so rapidly converted 



