PHYSICAL FEATURES. 9 



CHAPTER II.-PHYSICAL FEATURES. 



The chief physical characteristic of the country under review is 

 that of a vast sandy plain, in which except when rain is actually 

 falling, no running water is to be seen, diversified only by the rounded 

 forms of sandhills, or by isolated knolls and groups of hills composed 

 of solid rock, whose rugged and barren slopes rise abruptly from the 

 sea of sand surrounding them. Arid and barren as the country may 

 seem, however, especially to the traveller who only visits it during the 

 dry months of the winter and spring, it is not altogether a desert in 

 the strict sense of the term. Wherever water can be obtained from 

 wells, and whenever, as occasionally happens, there are favourable 

 rains, excellent crops of wheat and millet are raised, and the 

 whole country is clothed with a luxuriant crop of grass, affording pas- 

 turage to large herds of cattle and sheep. The " desert " thus supports 

 a large population, taught by experience to make the most of their 

 means of subsistence, precarious though they may be, and to store 

 up the superabundant harvests of the good years for use during less 

 favourable seasons. 



The largest and most lofty group of hills in the country is found 

 in the Siwana district, to the south of the great bend of the Luni, where 

 they reach an altitude of over 3,000 feet above the sea. A study of 

 the map will show that the hills are arranged in irregular groups of 

 individually isolated peaks or ridges, separated by broad expanses of 

 sand, in such a manner as to suggest that what we now see are the 

 highest points of continuous hill ranges, partly buried in sand. In- 

 deed the hills, viewed from an elevation, resemble nothing so much 

 as a number of rocky islands forming the crests of a mountainous tract 

 submerged beneath the sea, and it requires no great stretch of the 

 imagination to picture this region in some former age as one of flow- 

 ing rivers and fertile valleys, before some change of climate reduced 

 the power of the rivers to sweep back the ever increasing encroach- 

 ment of sand from the south. 



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