VEGETATION OF THE RIM AC VALLEY. 73 



which is a large sugar-plantation, the slopes on either 

 side of the valley become more continuous, and 

 gradually approach nearer together. The first trace 

 of vegetation visible from a distance was shown by 

 one of the cactus tribe, probably a Cereus, and as we 

 ascended I was able to distinguish two other species 

 of the same family. 



At many points in the valley, always on slightly 

 rising ground, shapeless inequalities of the surface.^ 

 marked with their rough outline all that now remains 

 of the numerous villages that in the days of the Incas 

 were scattered at short intervals. 



As we advanced, the slopes on either side became 

 higher and steeper, but were still apparently nearly 

 bare of vegetation until we reached Chosica, about 

 twenty-six miles from Lima, 2800 feet above the sea. 

 At this place it was formerly the custom to halt for 

 breakfast, but since the line has been re-opened, the 

 only eatables to be found are the fruits, chiefly 

 bananas and granadillas, which Indian women offer 

 to the passengers. 



Henceforward the line is fairly enclosed between 

 the slopes on either hand, everywhere rough and 

 steep, but, as is the nature of volcanic rocks, nowhere 

 cut into precipices. The gradient becomes perceptibly 

 steeper, being about one in thirty-three in the space 

 between Chosica and San Bartolome — about thirteen 

 miles. Here the change of climate begins to be dis- 

 tinctly marked. It is evident that during a great part 

 of the year the declivities are covered with vegetation, 

 though now brown from drought, and they show the 

 occasional action of running water in deep furrows 



