10 DICTIONARY OF ALTITUDES IN UNITED STATES. 



the results .of which can be absolutely depended upon for accuracy. 

 The United States Coast and Geodetic Survey has executed a vast 

 amount of leveling of the greatest accuracy, including a line across 

 the country from Sandy Hook through St. Louis, Denver, and Ogden 

 to Puget Sound. 



The United States Lake Survey and the Mississippi River and 

 Missouri River commissions have also made important contributions 

 by leveling numerous lines in the Mississippi Valley and about the 

 Great Lakes. 



The United States Geological Survey has, in connection with its 

 topographic work, carried on extensive leveling operations scattered 

 over many different localities in various parts of the country. This 

 work, done since the year 1895, has already reached such magnitude 

 as to form a very important aid in the adjustment of levels. 



Moreover, as above noted, the railroads have aided greatly in this 

 work of adjustment by carefully compiling the levels of their own 

 systems, and the elevations given by many of the larger railroad 

 companies of the country are nearly or quite as accurate as the pre- 

 cise levels above specified and can safely be used as primary lines. 



RAYNOLDS, CAPT. W. F. 



Under this authority are given the hypsometric results of the expe- 

 dition of Captain Raynolds to the country about the sources of the 

 Snake and Missouri rivers in 1860-61. All the work is barometric. 



SIMPSON, CAPT. J. H. 



Reconnaissance in Navajo Country, 1849 (Thirty-first Congress, 

 first session, Senate Document No. 6), and Explorations in the Great 

 Basin of Utah, 1859, published in 1876. The elevations were meas- 

 ured by barometer. 



UNITED STATES ARMY (u. S. A.). 



Under this heading are given the altitudes of certain army posts, 

 determined by barometer. 



UNITED STATES COAST AND GEODETIC SURVEY (u. S. C. & G. S.). 



The elevations credited to this source are of two classes one of 

 triangulation stations whose heights have been determined by refined 

 trigonometric methods, the other of lines of precise leveling referred to 

 above. 



UNITED STATES ENGINEER CORPS (ENGINEER CORPS) . 



Elevations given under this authority are the results of precise 

 leveling, executed in connection with river and harbor improvements. 



