3l8 PHYSICAL GEOGRAPHY. 



the banks being as a general statement very small. To this comparative 

 shallowness of earth, and'consequent prominence of the underlying rock, 

 we also owe the large amount of water-power which occurs on our rivers 

 in the lower portion of their course. Were the geological character of 

 our sea-coast the same as that of the Southern states, our rivers near the 

 sea would be worthless for water-power, having deepened their valleys 

 through the loose strata so as to be affected far inland by the rise of the 

 tide, while their size is such that they would be of little value for pur- 

 poses of navigation in comparison with the power which they now furnish 

 for our manufactvires. 



The character of the surface of New Hampshire should also be con- 

 sidered in its effect upon the water-power. Under this head the most 

 important inquiry is in regard to the contour or general elevation of the 

 state in different sections, including the arrangement and character of its 

 slopes, and the distinguishing features of its mountains, drainage basins, 

 and river valleys. 



From the tables of altitudes already given in this chapter, it is seen 

 that Connecticut lake, the principal source of our largest river, exceeds 

 1600 feet above the level of the sea. The descent of this river from this 

 point to the north line of Massachusetts is more than 1400 feet. This 

 total descent is distributed over the entire distance of its course, furnish- 

 ing a succession of valuable water-powers often equal to those which 

 have caused the rapid building up of such cities as Manchester, Lowell, 

 and Lawrence. Although no considerable distance along this river is 

 destitute of sufficient descent to produce upon improvement a valuable 

 water-power, it is not intended to convey the idea that the rate of fall is 

 nearly uniform along its entire course. By recurrence to the list of alti- 

 tudes, it will be seen that its descent in the first 1 7 miles, to the bridge 

 between West Stewartstown and Canaan, Vt., is about 600 feet; in the 

 next 44 miles, to the mouth of John's river in Dalton, the descent is about 

 200 feet ; in the next 24 miles its descent is again rapid, amounting to 

 about 400 feet, the course of the river being transferred, with a westerly 

 offset by the rapids of Fifteen-miles falls, from the Upper to the Lower 

 Connecticut valley. From the northern continuation of the latter valley 

 it receives the waters of the Passumpsic. In the remaining 1 1 3 miles of 

 its course along our western border, its descent is about 230 feet, which 



