SURVEYS OF FOREST RESERVES. ( 



The total amount of topogrraphy mapped comprises an area of 1,164 

 square miles, being aboat two-thirds ot the entire area. This required 

 the survey of 1 ,311 miles of roads. The triangulation of the whole area 

 is completed. TTcelve new station .s have been located. There have 

 been run 484 mile.s of spirit-level lines, and 141 bench marks have been 

 established, being about four-fifths of the ^hole number required. 



Cost of topography, including leveling and triangulation, to close of 

 .season. '^11,756. There has been a total of 535 miles of section and 

 township lines run, which includes 21 miles of retracements of old sur- 

 veys, at a cost of 65,-350. the total oo-t of the work being 617.106. The 

 land survey work cost, approximately, 61iJ per linear mile, which includes 

 the cost of new instruments and outi&ts. thus making the rate slightly 

 less than would have been allowed under land-ofSce regulations. 



Hxaminatian of forests. — ^Mx. H. ."?. Graves was employed as special ' 

 field assistant in this region. He commenced work early in July and : 

 concluded in the latter part of November, having examined the entire 

 region of the hills, including much land outside the limits of the reserve. 

 Topographic maps of this region, made on a scale of 1 : 125,000, by the 

 Survey, are used for the representation of much of the data obtained. 



The area of the reserve, which lies entirely in South Dakota, is 

 estimated at 967.6-sO acres, or about 1,500 square miles. It includes 

 practically all the forests oi the hiUs to the east, but on the north and 

 northwest there are large areas of forest which are not included. On 

 the other hand, in the southwestern part there are large tracts of open 

 country which are included in the reserve. 



The Black HiUs are situated between the Bellefourcl e and the South 

 Fork of Cheyenne Biver, between the forty-third and forty-fifth par- 

 allels of latitude and between the one hundred and third and one hun- 

 dred and fifth meridians. They are an isolated group of uountains, 

 whose general trend is north northwest and south southeast, and are 

 about 120 miles long by 40 mfles in width. The form of the uplift is 

 elliptical. From the central portion the stratified beds have been, in 

 part, removed, expo>ing the underlying granites in the eastern half, 

 while the western half is still covered by Carboniferous h'mestones. 

 The granite jwrtion is somewhat rugged, although the relief is on a 

 small scale. The Carbontferons portion has an undulating surface. 



Entirely surrounding this central jwrtion is an elliptic-shaped valley 

 of varying breadth,knomi as the "Kace Track.^ This in turn is inclosed 

 by a rim of ridges, or hogbacks, rangiiig in elevation from 200 to 800 

 feet above the plains. The mean altitude of the plains at the base of 

 the hills is about 3,000 to 3.500 feet above sea level, and the average 

 elevation of the hills above them is about 2,000 feet. The highest point 

 is Harney Peak, in the granite portion of thehUls, which has an altitiid^ 

 of 7.215 feet above sea level. In the northwestern portion of the hills 

 are several isolated peaks of volcanic rock which have broken through 

 the overlying .strata, and, owing to their greater hardness, they have 

 remained while the softer strata have been worn away. 



The exterior outlines of the main body of forest are, for the most 

 part, sharply drawn. In general the forest terminates abruptly at the 

 inside of the Bace Track, or the broad valley lying between, the main 

 portion of the hills and the hogbacks which encircle them. In certain 

 cases where these hogbacks are higher than elsewhere they also are 

 clothed with forests. Thus the Elk ^fountain Eange. the Pisgah HiUs, 

 the Inyankara Eange. and Bear Lodge Mountains are covered with 

 timber. In the southern portion of the hUls the outline of the timber 

 is more irregular than elsewhere and has been pushed back within the 

 hiUs by forest fires. 



