1 



550 



GEOLOGY OF THE BLACK HILLS. 



Observations made at Signal Station, Cheyenne, August 20, 1875. 

 Observer, A. C. Dobbins, U. S. A. 



Bar. st'd 133 



a 

 u 



10.19 a. m. 

 2.00 1). m. 

 2.44 



lU. 



24.300 

 24.310 

 24.373 



Att. tb. = 63.5 

 = 09.0 

 = 68.0 



Ex. th. 64.0 

 = 68.0 

 = 53.0 



Keduced to 32° h = 24.328 



Table I gives for 



Table I gives for 

 Approx. diff. level 



D X {t+f - 64) 



h 23,223.4 



h' 22,164.7 

 = D = 1,058.7 



= + 66.9 



t =61.7 

 i' = 59.2 



t + t' 120.9 



900 





Second approx. diff. 

 Table III for D' gives 

 Table IV for D' gives 

 Table V for h 24.33 inches 



= D' = 1,125.6 



= + .1 

 = + 3.0 



= + .7 





Terry Peak above Cheyenne 

 Cheyenne above sea level 



1,129.4 



0,085.9 





Terry above sea level 

 Harney above sea level 



7.215.3 feet. 



7.308.4 feet. 





Terry below Harney 



163.1 feet. 



. 



