1835.] TERRACES OF SHINGLE. 315 
like good children, follow her. ‘The affection of these animals 
for their madrinas saves infinite trouble. If several large troops 
are turned into one field to graze, in the morning the muleteers 
have only to lead the madrinas a little apart, and tinkle their 
bells ; and although there may be two or three hundred together, 
each mule immediately knows the bell of its own madrina, and 
comes to her. It is nearly impossible to lose an old mule; for if 
detained for several hours by force, she will, by the power of 
smell, like a dog, track out her companions, or rather the 
madrina, for, according’ to the muleteer, she is the chief object 
of affection. The feeling, however, is not of an individual 
snature; for I believe I am right in saying that any animal with 
a bell will serve as a madrina. In a troop each animal carries 
on a level road, a cargo weighing 416 pounds (more than 29 
stone), but in a mountainous country 100 pounds less; yet with 
what delicate slim limbs, without any proportional bulk of muscle, 
these animals support so great a burden! The mule always 
appears to me a most surprising animal. That a hybrid should 
possess more reason, memory, obstinacy, social affection, powers 
of muscular endurance, and length of life, than either of its 
parents, seems to indicate that art has here outdone nature. Of 
our ten animals, six were intended for riding, and four for carry- 
ing cargoes, each taking turn about. We carried a good deal of 
fuod, in case we should be snowed up, as the season was rather 
late for passing the Portillo. 
March 19th.—We rode during this day to the last, and there- 
fore most elevated house in the valley. The number of inha- 
bitants became scanty; but wherever water could be brought 
on the land, it was very fertile. AJl the main valleys in the 
Cordillera are characterised by having, on both sides, a fringe or 
terrace of shingle and sand, rudely stratified, and generally of 
considerable thickness. These fringes evidently once extended 
across the valleys, and were united; and the bottoms of the 
valleys in northern Chile, where there are no streams, are thus 
smoothly filled up. On these fringes the roads are generally 
carried, for their surfaces are even, and they rise with avery gentle 
slope up the valleys: hence, also, they are easily cultivated by 
irrigation. They may be traced up to a height of between 
7000 and 9000 feet, where they become hidden by the irregular 
