DK. F. WEL-WITSCH Oli THE GUM COPAL IX Ai^GOLA. 289 



which flows immediately into rivers or the sea, thereby doing little 

 good to the thirsty sandy soil. Still these rains,*which produce 

 here and there small rivulets, furrowing the soil in every direc- 

 tion, enable even the sandy plains to bring forth for a few mouths 

 during the year a lovely green, chiefly of Graminese, Cyperacese, 

 Leguminosse, and Compositae. Immediately after these heavy 

 rains, the temperature rises to so high a degree that, within a 

 few days, a great number of delicate plants fade away ; and even 

 shrubby plants suffer sometimes so much that they do not blos- 

 som, or do not bring forth ripe fruit, during several years. This 

 may be one of the many iieasons which have caused the gra- 

 dual dwindling away, and I might say the dwarfing, of the vege- 

 tation in this region. The breadth of this littoral region, from 

 the shores of the Atlantic Ocean to the foot of the first high 

 terrace, varies very much, according to the different curves of 

 this last-named mountain-ridge : sometimes (for instance, near 

 Libongo and the Dande) it only measures a few miles ; whilst at 

 other places, near the Bengo Kiver, it extends inward fifty or 

 more geographical miles. lu many places where the mountain-ridge 

 of the terrace is intercepted by wide clefts, or by broad valley 

 slopes, this littoral region is extended far into the mountain- 

 terrace itself, forming in the middle of the primeval forests larger 

 •or smaller sand oases, covered with low shrubs or single dwarf 

 trees. On the other hand, the luxuriant and varied vegetation 

 of the primeval forests reach sometimes from the terrace close 

 down to the Atlantic coast district, especially along the narrow 

 vales abutting on the sea, and still more so those extending along 

 the banks of the larger rivers like the Zaire, the Loge, Dande, 

 Bengo, Cuanza, and the Cotumbella. In such places the traveller 

 suddenly finds himself, to his great surprise, transported within 

 a few paces from a barren desert into a landscape abounding in 

 the richest crops ; among which are seen the bright green of the 

 Oil Palm, and the majestic foliage of the graceful Eaphias, whilst 

 the towering crowns of the Bombax, several varieties of Ficus, 

 and the beautiful slender Cocoa Palm, sometimes alone and some- 

 times in small groups, spread high above the exuberant mass of 

 vegetation. 



Prom the fact of the coast district penetrating here and there 

 ^ith its vegetation into the high mountain-terrace, it follows that 

 ^ts limits towards the interior of the continent do not form a 

 clearly defined curve, but rather a sharp zigzag line; which 

 a*3couat8 for Gum Copal being sometimes found in places far 



