DESCRIPTION OF AUTHORITIES. 



GODDARD. 



These determinations are by level from preliminary railroad surveys 

 made by the Central Pacific Railroad Company of California. Like 

 all preliminary work, they are not in the highest degree reliable. 



GUYOT. 



Nearly all the elevations given under this authority are in the 

 Appalachian region, and were determined by barometer. They are of 

 the highest character of this class of work. Most of the figures have 

 been compiled from Professor Guyot's articles in the American 

 Journal of Science and Arts. 



HAYDEN, DR. F. V. 



Under this authority is given all work done by the United States 

 Geological and Geographical Survey of the Territories. All deter- 

 minations are barometric or trigonometric resting on barometric 

 bases. 



IVES, LIEUT. J. C. 



Report of Colorado Exploring Expedition (Thirty-sixth Congress, 

 first session, Senate document). All determinations are barometric. 



JENNEY, PROF. WILLIAM P. 



These heights were abstracted from the Atlas of the Black Hills. 

 All determinations are barometric. 



JONES, CAPT. W. A. 



Report of Expedition to Northwestern Wyoming and the Yellow- 

 stone Park, 1873. All determinations are barometric. 



KING, CLARENCE. 



This reference is mainly to the work of the Geological Exploration 

 of the Fortieth Parallel. All determinations are barometric or 

 depend upon barometric bases. 



MASSACHUSETTS TRIGONOMETRIC SURVEY (MASS. TRIG. SURVEY). 



This includes altitudes of stations determined trigonometrically 

 by a survey under the charge of Mr. Simeon Borden. 



MEXICAN BOUNDARY SURVEY. 



The altitudes given under this heading were determined by 

 barometer by the first survey of the boundary. 



MINNESOTA GEOLOGICAL AND NATURAL HISTORY SURVEY (MINN. 



STATE SURVEY). 

 These elevations were, in the main, determined by aneroid. 



