10 BULLETIN 1244, U. S. DEPARTMENT OF AGRICULTURE. 



Further details explaining the periods covered by the data given 

 in Table 7 for the several stations (all dates inclusive) are as follows : 



Redfield, S. Dak.— All data are for the years 1898 to 1922. 



Havre, Mont. — The precipitation data and absolute maximum and minimum 

 temperatures are for the years 1880 to 1922; longest and shortest growing seasons 

 and frost data, 1910 to 1922; other data, 1916 to 1922. 



Moccasin, Mont. — Precipitation data, 1898 to 1922; other data, 1909 to 1922. 



Dickinson, N. Dak. — Precipitation data, frost data, and absolute maximum 

 and minimum temperatures, 1892 to 1920; evaporation data, 1907 to 1921; 

 mean temperature, 1895 to 1920; mean maximum and mean minimum tempera- 

 ture, 1901 to 1920; wind velocity, 1908 to 1921. 



Mandan, N . Dak. — Precipitation data, frost data, and absolute maximum and 

 minimum temperatures, 1875 to 1922, these data for the years 1875 to 1913 being 

 from records at Bismarck; mean temperatures from records at Bismarck for 

 1878 to 1920; other data, 1914 to 1922. 



Williston, N. Dak. — Precipitation data, absolute maximum and minimum tem- 

 peratures, 1879 to 1920; evaporation data, 1909 to 1918; mean, mean maximum, 

 and mean minimum temperatures, 1882 to 1920; frost data, 1894 to 1920: wind 

 velocity, 1909 to 1920. 



Hettinger, N. Dak. — Precipitation data, 1907 to 1920; wind velocity, 1913 to 

 1920; mean temperatures, 1911 to 1921; absolute maximum and minimum 

 temperatures, 1908 to 1920; frost records, 1909 to 1920; evaporation data, 1911 

 to 1921 (exclusive of 1913). 



Edgeley, N.'Dak. — Precipitation data, 1901 to 1920; evaporation data, 1909 

 to 1920; mean, absolute maximum, and absolute minimum temperatures, 1907 

 to 1921; wind velocity, 1910 to 1920; frost data, 1903 to 1920. 



Sheridan, Wyo. — Precipitation data, 1893 to 1920; evaporation data, 1918 to 

 1921; mean, mean maximum, and mean minimum temperatures, 1908 to 1920; 

 mean, absolute maximum, and absolute minimum temperatures, 1896 to 1920; 

 frost data, 1900 to 1920 (exclusive of 1903 and 1904) ; wind velocity, 1917 to 1920. 



Belle Fourche, S. Dak. — Precipitation data, frost data, and mean, absolute 

 maximum, and absolute minimum temperatures, 1908 to 1922; evaporation data 

 and wind velocity, same years; mean maximum and mean minimum tempera- 

 tures, 1912 to 1921. 



Ardmore, S. Dak.— Precipitation data, 1912 to 1922; other data, 1913 to 1922. 



SOILS. 7 



In a region as extensive as the northern Great Plains the types of 

 soil are so numerous that no attempt is here made to give them 

 more than a general consideration. Each of the 12 groups shown 

 on the accompanying map (fig. 2) includes numerous types varying 

 in characteristics and ranging in texture from sand to clay. 



In three of the divisions — the mountain areas, the sand hills, and 

 the Yellowstone group — no attempt has been made to differentiate 

 the soils. The mountain areas are for the most part outside the 

 region here considered. The sand hills in the main are of little value 

 except for grazing purposes, although interspersed with flats having 

 a comparatively shallow water table on which alfalfa and other forage 

 crops are successfully grown. The Yellowstone group includes the 

 Bad Lands and other hilly areas with shallow soils, areas of relatively 

 smooth land with shallow soils (as in eastern Wyoming), areas of 

 shale outcrop (as in eastern Montana), and "slick-spot" areas. 

 These lands in the main are not capable of cultivation, although they 

 are of more or less value for grazing. 



The other soils of the region, which for the most pari are sufficiently 

 smooth for the usual farming operations, appear on the .map a- a 

 series of belts nmning north and south and interrupted by the 



• i ontrlbuted i>\ the Bureau of Soils of the United States Department of Agriculture. 



