206 



With the elevations of these stations cietermiDed, the heights of un- 

 visited points were obtained by applying the difference of level, as 

 obtained from the vertical angle, to the height of the station from which 

 the angle was taken. As most of the unvisited j)oints are sighted from 

 many stations, we have for each a uuuiber of determinations of which 

 the mean is taken. Many of these points are quite as well determined 

 as some of the stations. 



As it was impossible to connect all the peaks with the scheme of trig- 

 onometric levels, it was thought best to give the heights of such as near 

 as it could be obtained from the data at hand. 



All these, it must be understood, depend on a single reading of the 

 mercurial barometer, not of the small aneroid. The latter instrument 

 was found to be worse than useless. Only one height depends on an 

 aneroid reading, that is Bear Creek Pass, but as here we had two differ- 

 ent sets of readings of three different aneroids, compared each morn- 

 ing with the mercurial barometer, I thought best to put the height in 

 the list, but it must not be considered as very accurate. 



In the following table are given as nearly as may be, the heights of 

 all the peaks in the San Juan country above 13,000 feet, besides stations 

 and other points of interest. Some of the latitudes and longitudes have 

 been calculated, while the others have been taken from Mr. Wilson's 

 plot of his secondary triangulation, at a scale of two miles to one inch. 

 Some of these peaks being i^oints of the primary triangulation, their 

 latitude and longitude will be more accurately determined when that 

 work is huished. 



The first column in the table indicates the topographical designation 

 of each peak. The double numbers indicate unvisited stations. For 

 instance, 14 — 9 signifies the fourteenth point sighted from station 9, 

 which ever afterward bears that designation u.uless occupied as a sta- 

 tion. The term '• Baker's Park rectangle" signifies the projection rect- 

 angle included between latitude 37° 45' and 38° and longitude 107° 30' 

 and 107° 45', in which Baker's Park is situated. On the map the name, 

 by a sad oversight, was omitted, but its position may be known from 

 the fact that Howardville and Silverton are situated within it. 



