4 



548 



GEOLOGY OF THE BLACK HILLS. 



tions on Harney Peak were made shows that there was no local disturb- 

 ance east or west of a line joining Clieyenne and the center of the Black 

 Hills, and the deduced height of Harney can be considered as very near 

 the truth, not more than 50 feet in error, I think. 



The height of Terry, as deduced fi-om barometrical observations on 

 August 20, and from a zenith distance from Harney, agree within 12 feet. 



The observations on Harney were all made on the highest point, which 

 irave us much trouble and risk of life and limb to reach. The mean of four 

 of Green's compensated aneroid barometers gave as the height of Harney 

 7,440 leet. 



As my altitude of Harney is so widely different from that found by 

 Colonel Ludlow, in 1874, I give both observations and computations here 

 complete. 



The altitude of the railroad track at Cheyenne is, according to an 

 elaborate investigation by Mr. James T. Gardner, 6,075.28 feet, and by 

 measurements by Dr. McGillycuddy and myself, with a theodolite, the 

 cistern of the standard barometer in the signal office is 9.58 feet above the 

 rails This gives for lieigbt of cistern above the sea-level 6,085.86 feet, 

 exactly one geographical mile. 



Observations made on the summit of Hartley Peak, July 25, 1875, lat. 43°-52' N. 



Observer, H. P. Tuitle. 



Bar, 2123 



10.00 a. 

 10.30 

 10.45 

 11.00 



111. 



23.248 

 23.238 

 23.242 

 23.240 



Att. 



th. 



= 63.6 

 = 64.9 

 = 61.6 

 = 65.6 



Meaus 



23.244 



63.9 



Kednced to Chej 



enne standard 



-.003 









Keduced to 32° 







-.073 



= h' 









23.168 





Ex. th. = 59.5 

 = 00.5 

 = 58.0 

 = 59.2 



59.3 = P 



