2S6 PHYSICAL GEOGRAPHY. 



They will be found there, arranged in the description of river systems, 

 together with heights of the principal lakes and ponds of the state, and 

 others along lines of water-sheds, many of which, taken from baromet- 

 rical measurement, are not to be regarded as exact. 



The altitudes of principal points along the main water-shed of New 

 Hampshire, separating the waters of the Connecticut from those of the 

 Androscoggin, Saco, and Merrimack, being of the first importance as 

 illustrating the topography of the state, have been already given in a pre- 

 ceding chapter. Also, in the same chapter, are to be found heights along 

 the boundaries of New Hampshire. 



The lists of altitudes of villages, of some of the largest lakes and 

 ponds, of the largest rivers at a few places, and of other points of inter- 

 est throughout the state, have been derived from various sources, the 

 degree of probable accuracy being indicated by the difference in type. 



The table of heights of the mountains and principal hills of the state, 

 with miscellaneous points in the mountain region, comes, to a large extent, 

 from barometrical measurement. Others, both in this list and in that of 

 villages, &c., have been copied from different publications, in which case 

 the original authority is usually given, exact measurements being distin- 

 guished by heavy type. A very valuable list of altitudes, principally of 

 mountains and hills, has been obtained, in connection with the triangula- 

 tion of the state under the U. S. Coast Survey, by Prof. E. T. Quimby; 

 " these, so far as the survey has been already extended, are given on p. 242. 



Geological Skctions. 



Fourteen general sections have been measured, extending across the 

 state in parallel lines, nearly east and west. Their geological character 

 will be given subsequently ; but it is the proper place here to state what 

 figures have been used in drawing their profiles, as exhibited in connec- 

 tion with the rock specimens in the state museum at Hanover. Exact 

 determination by levelling has been secured for the starting-point 

 wherever practicable, and the aneroid barometer has been employed for 

 determining heights beyond. The details cannot very well be presented 

 with each determination, as they are too voluminous, and not of great 

 consequence. 



The names of residents, streams, hills, and mountains are taken from 



