334 CHARLES DARWIN 



she is an old steady mare, with a little bell round her neck; 

 and wherever she goes, the mules, 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; although 

 there may be two or three hundred together, each mule im- 

 mediately 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 indi- 

 vidual 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 indi- 

 cate that art has here outdone nature. Of our ten animals, 

 six were intended for riding, and four for carrying 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 ipth. We rode during this day to the last, and 

 therefore most elevated, house in the valley. The number of 

 inhabitants became scanty; but wherever water could be 

 brought on the land, it was very fertile. All the main valleys 

 in the Cordillera are characterized 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, 



