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 



u 

 u 



10.19 a. m. 

 2.00 p. m. 

 2.44 



in. 

 24.300 

 24.310 

 24.373 



Att. th. = 63.5 

 = 69.0 



= 68.0 



Second approx. cliff. 

 Table III for D' gives 

 Table IV for D' gives 

 Table V for h 24.33 inches 



Terry Peak above Cheyenne 

 Cheyenne above sea level 



Terry above sea level 

 Harney above sea level 



Terry below Harney 



= D' = 1,125.6 



= + .1 



= + 3.0 



= + .7 



Ex. th. 64.0 

 = 68.0 

 = 53.0 



Beduced to 32° h = 



24.328 





t = 61.7 

 V = 59.2 



Table I gives for 





h 23,223.4 



t + V 120.9 



Table I gives for 

 Approx. cliff, level 

 D x {t+f - 



64) 



y 22,164.7 



= D = 1,058.7 



= + 66.9 





900 







1,129.4 



6,085.9 



7.215.3 feet. 



7.368.4 feet. 



153.1 feet. 



