330 NOTES OF A BOTANIST chap. 
river. I propose here to treat of the lower part of these two rivers, 
and especially of the Chira, in some detail. 
The configuration of the coast-region from Cape Blanco to and 
beyond the Piura is as follows : — On the western margin rise steep 
cliffs to a height of from 200 to 300 feet, either directly from the 
sea or with an intervening beach uncovered at low-water, and 
usually with a low reef of rocks at about half-tide, whereon even 
the gentle waves of the Pacific break in a dangerous surf. Having 
surmounted the cliff, we are on what is called the tablazo, a 
plateau rising very gently to eastward, in some places slightly 
undulated, and in others with ridges of considerable height rising 
out of it, the whole so bare of vegetation that there are places 
where not a single tree, much less an herb, can be distinguished 
within the limits of vision. A bold abrupt ridge, called the Silla 
de Payta, rises immediately to southward of that town to a height 
(according to Captain Kellett) of 1300 feet; but a far more 
important range of hills, beginning from near the sea, a little to 
northward of the mouth of the Chira, runs with a direction of 
E.N.E. all the way up between the rivers Chira and Tumbez, till 
it mingles with the Andes towards the sources of the latter 
river. ... I suppose these hills to rise, even in their western 
part (which is all I have seen of them), to from 2000 to 3000 
feet ; to eastward, as they near the Andes, they must be far 
higher. Viewed from the south, they appear entirely bare of 
vegetation, but when they come to be examined their deep 
ravines are found to contain a few scattered Cactuses, Algarrobos, 
and other trees ; and I am told that on their northern slope there 
is considerably more permanent vegetation, much as on the hills 
of Chanduy and St. Elena, which, although of far less extent, 
have quite the same aspect and structure. 
The country to southward of the river Piura is known as the 
Despoblado (or Desert) of Sechura ; but in reality that term might 
be extended to the whole desert region which stretches northward 
to the skirts of the forests of the Gulf of Guayaquil, for the narrow 
strip of vegetation along the courses of the Chira and Piura are 
mere oases in that vast desert. 
The deep valley along which the Chira flows to the sea has 
plainly been excavated by the action of water, and if any 
depression have originally existed on the tablazo along the same 
line it must have been very slight, as there is now no appreciable 
sloping towards it. Its sides are steep cliffs, scarcely at all 
furrowed transversely on the southern side, but on the northern 
side in most places very much broken up into ravines and 
alternating peaked ridges, whose origin may be traced to the 
effect of the rare but torrential rains descending the rugged slopes 
