SURVEYS OF FOREST RESERVES. 19 



the Salmon River ; thence in an easterly direction along the middle of the channel 

 of said river to the point of intersection for the unsnrveyed range line between 

 ranges eighteen (18) and nineteen (19) east; thence northerly along said unsnrveyed 

 range line to the point of intersection -with the bonndary line between the States of 

 Idaho and Montana; thence in an easterly direction along said State boundary line 

 to the point for the unsnrveyed range line between runges nineteen (19) and twenty 

 (20) west, principal meridian, Montana; thence northerly along said range line to the 

 base line; thence westerly along said base line to the southeast comer of township 

 one (1) north, range twenty (i'O) west; thence northerly along the range line to the 

 northeast corner of said township ; thence westerly along the surveyed and unsnr- 

 veyed township line between townships one (1) and (2) north, to the point for the 

 southeast corner of township two (2) north, range twenty-two (22) west; thence 

 northerly along- the unsnrveyed range line between ranges twenty-one (21) and 

 twenty-two (22) west, allowing for the proper offsets on the Urst (1st) and second 

 (2nd) standard parallels north, to the point for the northeast corner of township ten (10) 

 north, range twenty-two (22) west; thence westerly along the unsurveyed township 

 line between townships ten (10) and eleven (11) north, to the point of intersection 

 with the boundary line between the States of Montana and Idaho; thence along said 

 State boundary line to the point for the unsurveyed township line between town- 

 ships thirty -eight (38) and thirty-nine (39) north, Idaho ; thence westerly along said 

 township line to the point for the northwest comer of township thirty-eight (38) 

 north, range ten (10) east ; thence southerly along the unsurveyed range line between 

 ranges nine (9) and ten (10) east, to the point for the southwest corner of township 

 thirty-seven (37) north, range ten (10) east; thence westerly along the unsure eyed 

 seventh (7th) standard parallel north, to the northeast corner of township thirty-six 

 (36) north, range five (5) east, the place of beginning. 



Surreys. — Probably there is no other portion of the country, exclu- 

 sive of Alaska, about which there is so little known as of the territory 

 included in the Bitterroot Forest Reserve. It was therefore necessary 

 to commence ab initio, as nothing whatever was available from a topo- 

 graphic standpoint. The first step was to determine an astronomic 

 position, measure a base line, and expand a system of triangulation 

 which would serve to furnish starting points for the topographic map- 

 ping. A location for the astronomic station was selected in the town 

 of Hamilton, Mont., and the latitude and longitude of a masonry pier 

 built at this point were determined. The latitude was obtained by 

 observations on 60 pairs of stars, and the longitude by time observa- 

 tions and telegraphic exchange of clock signals with TVashiugton Uni- 

 versity, at St. Louis, Mo., on iive nights. A permanent meridian mark 

 was also set one-half mile south of the astronomic pier. A base line 

 was twice measured with a 300-foot tape under a constant tension of 20 

 pounds, several hundred thermometric readings of the temperature of 

 the tape being obtained during the process of measurement. The total 

 length of this line was 5.7 miles, and the difference between the two 

 measurements, after all corrections had been applied, was about 1 inch. 

 Triangulation was expanded from the base line over an area of about 

 6,500 square miles, 1,000 miles being covered so that no further work is 

 necessary, and the remaining 5,500 being covered in a manner sufBcient 

 to provide a basis for a reconnaissance map, including the whole area 

 of the Bitterroot Forest Eeserve. 



Topographic work was prosecuted by two separate parties, one being 

 engaged in preparing a detailed map of the territory included in and 

 adjacent to the Bitterroot Valley, and the other party being detailed to 

 secure data for the reconnaissance map above referred to. About 600 

 square miles were included in the detailed survey, and the remaining 

 portion of the reserve was mapped by the reconnaissance survey. On 

 the maps resulting from each of these surveys will be shown, with con- 

 siderable detail, the extent and variety of the forest areas, and also 

 those areas that have been denuded by forest fires, as well as those 

 which are naturally bare of timber. There was also obtained informa- 



