64 Field-Labourers 



several feet, and in this way make it easier for the rain 

 and the air to reach the rock below; and wherever 

 these penetrate, there, as has been already shown, 

 decay must surely follow, slowly or rapidly, according 

 to the nature of the rock. In this way, therefore, 

 burrowing animals, whether rabbits, ground squirrels, 

 or even worms, have helped to deepen the soil ; and 

 by the lives and labours of these and similar animals, 

 long continued, some of the most fertile lands have 

 been prepared. 



We will now look at their work more in detail- 

 All over the Pampas of South America there are 

 frequent groups of holes excavated by the bizcacha, a 

 curious, rabbit-headed animal, as large as a badger ; 

 and in South America also, but chiefly in the moun- 

 tain valleys, dwells the bright-eyed, soft-furred little 

 chinchilla, not much larger than a squirrel, whose 

 burrows are found together in such large numbers as 

 to cause almost as much inconvenience as those of the 

 bizcacha. 



In the western regions of North America, from 

 Mexico to the Arctic Ocean, as well as in the northern 

 parts of the Old World, there are a large number of 

 small animals called by the general name of ' ground- 

 squirrels,' and resembling tree - squirrels in many 

 respects, though some of their habits are very dif- 

 ferent. Like the tree-squirrels, they lay up stores 

 of food, but, unlike them, they burrow in the ground, 

 and live together in large villages instead of in 

 pairs. 



One of these, the Chipmunk or Hackee, abounds in 

 parts of North America, where it makes very extensive 

 excavations, considering its size, which is less than that 



