A maximum of 98 is recorded in one year, and a minimum of -38 Fahrenheit. The soil of the valleys is a fertile loam, but irrigation is needed for the successful prosecution of agriculture. The great mineral resources of Wyoming have as yet scarcely been developed. At Evanston, Carbon, Rock Springs, and several other points on the line of the Union Pacific, lignite has been mined. The coal is of good quality and is shipped to many of the Territories, besides furnishing an ample supply for locomotives.
Iron ore is abundant, and consists principally of pure red hematites of great value.
Copper, lead, plumbago and petroleum also occur. Much gold has been taken from the mountain gulches of the Sweetwater country, and auriferous quartz veins of great value are worked in the neighborhood of Laramie City. Valuable deposits of soda exist in the valley of the Sweetwater. The deposits of sulphate of soda are from ten to fifteen feet in thickness, and are almost chemically pure. The first settlements within its limits were made in 1867, during the construction of the Union Pacific railroad, and the Territorial organization was completed on May 10, 1869.