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, jri 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 

 nature ; 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 

 food, 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. All 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 a very 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 irregulai 



