300 SURFACE OF THE PLAINS. [CH. VII. 



extend, in parts, at least, to the coast ranges on the east, 

 appears to be very limited on the opposite or western side; 

 a desert country from which it did not receive, as far as I 

 could discover, a single tributary of any importance. A 

 succession of low ridges seemed there to mark the extent of 

 its basin, nor did I perceive in the country beyond, any 

 ranges of a more decidedly fluviatile character. 



The average breadth of the river at the surface of the water, 

 when low, is about fifty yards, but oftener less than this, and 

 seldom more. Judging from the slight fall of the country, 

 and the softness and evenness of the banks (commonly in- 

 clined to an angle with the horizon of about 40°), I cannot 

 think, that the velocity of the floods in the river ever exceeds 

 one mile per hour, but that it is in general much less. At this 

 time the water actually flowing, as seen at one or two shallow 

 places, did not exceed in quantity, that which would be ne- 

 cessary to turn a mill. The banks every where displayed one 

 peculiar feature, namely, the effect of floods in parallel 

 lines, marking on the smooth sloping earth, the various 

 heio-hts to which the waters had indifferent floods arisen. 



Some of the hollows behind the immediate banks on both 

 sides, contained lagoons ; in several of these, reeds had 

 taken the place of water ; in others the first coating of vege- 

 tation, which the alluvium receives on exposure to the sun, 

 consisted of fragrant herbs, and amongst them we found the 

 scented trefoil (" CiMomba"),* which proved an excellent 

 anti-scorbutic vegetable when boiled. It was found, how- 

 ever, only at three places. 



The surface of the plains nearest the river, is unlike any 

 part of the earth's face, that I have elsewhere seen. It is as 

 clear of vegetation as a fallow field, but it has greater inecpia- 

 lity of surface, and is full of holes. The soil is just tenacious 

 enough to crack, when the surface becomes so soft and loose, 

 that the few weeds which may have sprang up previous to 

 desiccation, seldom remain where they grow, being blown 



* TriijonrUa iuovissimii, for the fiescrii)tion of which plant, sec page '25.3. 



