SURFACE. 31 



islands in the larger streams are a favourite home for him ; 

 for, though extremely active and industrious on occasions, 

 he does not make a dam except when forced to do so by 

 the scarcity of water. He works from necessity, not 

 from the love of labour. The amount of damage a family 

 of beavers can do in the way of cutting down trees is 

 wonderful. They eat only the bark of the more tender 

 branches, and a good-sized tree lasts but a little while. 

 Many islands are kept denuded of trees by these animals, 

 and they do vast damage even in the thicker and more 

 vigorous growth of the canons. 



The treelessness of the high plains is caused by the 

 lack of water, and high winds ; of the lower plains, by 

 wind, fire, and beaver. As the third plain gradually 

 blends with the great alluvial deposit of the Mississippi 

 Valley, the timber increases in variety, size, and vigour of 

 growth. 



The broadest expanse of the second plain extends 

 from the great central mass of mountains in a direction 

 a little east of south, including the Staked Plain, and 

 terminating in the so-called Guadalupe Mountains of 

 Texas. It is perfectly treeless, except on its south-easterly 

 edge, where it is marked by two extraordinary belts of 

 woods called the ' Cross Timbers' 



The larger of these belts is about an average of twelve 

 miles broad, the smaller about eight miles. The 'timber' 

 is composed of a great variety of trees and shrubs, oak 

 predominating. It is not a heavy growth ; but many of 

 the trees are of good size, and the whole is a fair average 

 forest. Starting on the high arid edge of the Staked 

 Plain, these belts pursue a course from north-west to 

 south-east. This outline is very irregular, but they keep 

 a general parallel course at an average distance of some 

 fifteen miles apart, never, I am told, once joining each 

 other until both are finally blended and lost in the heavy 

 timber lands of the Brazos and Trinity Eivers. I have 

 crossed these belts but once, many years ago. They 



