82 NATURAL HISTORY OP 



AFRICA. 



OF Africa, the most striking feature is the tabular 

 form of its structure, standing immoveable, like a huge 

 bulwark, almost centrally beneath the equator, without 

 a plentiful vegetation, almost without forests ; with few 

 undrained lakes, and, consequently, few great rivers, 

 who derive their supplies of moisture from clouds 

 coming from distant regions, and furnishing a diminish- 

 ing supply ; for their is an acknowledged dessication in 

 progress, observed alike in Morocco, at the Cape, and 

 most in Abyssinia. Perhaps the oldest of the conti- 

 nents, it appears exhausted. With a vigorous animal 

 and vegetable life, thinly scattered, or confined to par- 

 ticular valleys, and with proofs of a desert state so 

 remote, that no other region can produce a similar 

 example ; namely, in the Baobabs (Adansonia digit- 

 tata), of ninety feet in circumference, a bulk so enor- 

 mous, as to induce Adanson to assert, that they contain- 

 ed full six thousand rings of annual growth ; that is, 

 an age which no other living organic body on earth can 

 claim. * In this great region, the Nile alone, of all 



* There are oaks in France, Switzerland, and even in 

 Great Britain, above thirty feet in circumference, which 

 may be 3000 years old. A chestnut on Etna, not one of the 

 largest or oldest, left a portion of a side shoot, not contain- 

 ing the inner core or circles, which, nevertheless, afforded 

 1700 rings of annual growth. Baobabs thrive best on arid 

 plains. 



