Chap}iia)is Travels in South Africa 213 



The deserts themselves are another very interesting subject of 

 inquiry. We have often wondered whether the degree to which 

 antient sea bottoms are covered with vegetation might not be used 

 as a measure of the relative time which has elapsed since they 

 became dry land. Of course a great deal would depend upon 

 accessory circumstances, and more especially the amount of irriga- 

 tion enjoyed by each, but we imagine it to be indisputable that, 

 ceteris paribus, the longer the sea bottom has been exposed the 

 more will it be clothed with vegetation, and the higher will be the 

 character of the vegetation upon it. And in a general way we 

 think that this is visible in all the different raised sea-bottoms of 

 any magnitude with which we are acquainted. Which is the sea- 

 bed which has been most recently raised ? We imagine the Sahara 

 and its continuation in Arabia, the deserts of Scinde, the deserts 

 in Central Asia, and the salt lake deposits between the Rocky and 

 the Cascade Mountains in North-west America. What is their 

 state? Unmitigated barrenness, nothingbutsandand gravel, without 

 vegetation, except in patches and spots favoured by irrigation. 

 We have not space to turn a digressive eye upon the relative con- 

 ditions of age and vegetation in these and the North American 

 prairies of older exposure, the Brazilian forest plains, the pampas, 

 the interior of Australia, etc. It will be sufficient to contrast the 

 Sahara with the Kalahari and other deserts in the interior of 

 Southern Africa. The original condition and latitude are not un- 

 like, but they are immensely different in age ; the Sahara the 

 youngest, the Kalahari perhaps the oldest desert on the face of the 

 globe ; and what is their present state ? — waterless deserts both — 

 but the one a mere deposit of gravel or shifting sand, the other 

 provided with a dense vegetation peculiar to itself Mr Chapman 

 thus describes the latter : 



" The country over which we had been travelling since leaving the Bamanwato 

 is called the "desert," and travellers going to "the lake" from the colony are 

 obliged to go round it by the course we were now steering as the most practicable. 

 Could they make direct for the lake through the country of the Bakwain or 

 Bawanketze tribes they might reach their destination in half the time. Though 

 called a desert the reader must not picture to himself another Sahara, for although 

 a sandy country and devoid of water, excepting a few scanty wells at intervals 

 of forty cr fifty miles, it is nevertheless fertile, the grass gi'owing most luxuriantly, 

 and large forests of trees of many kinds abound" — (vol. i., p. 54). 



' ' We started at one o'clock the next day, and laboured through the heavy 

 sand and dense bush, the oxen coughing and nearly choked. Although every- 

 thing in this so-called " desert " gi-ows most luxuriantly, and grass and herbs 

 most exuberantly, we found no water" — (vol. i., p. 50). 



