HYDROLOGY. 175 



the time of the government survey, and thereby indicates the changes 

 that have since ensued. These changes have been much more marked in 

 the forest regions than in the more open country, and are so intimately 

 connected with the clearing away of the timber that it is a fair infer- 

 ence that this is the main cause. 



The timber is often very heavy, and consequently permits but a 

 very feeble undergrowth. The removal of the original forest thus 

 leaves the surface almost entirely bare, and it is usually at once put 

 under cultivation. The effect of so great a change would naturally 

 make itself felt upon the drainage of the region. To the extent to 

 which this has gone thus far, it has doubtless on the whole been a 

 benefit to the region, as it has induced a drier, lighter, warmer soil, 

 and more healthful atmosphere. But the limit of benefit in this di- 

 rection may be assumed to have been reached except in certain locali- 

 ties, and the danger now to be apprehended is that it will proceed to 

 an injurious extent. This, however, can easily be avoided, if clearly 

 foreseen and justly appreciated. 



