leys, being well sheltered, have generally a mild and pleasant climate. The mean temperature for January is 27.9° at Salt Lake City, 24.1° at Snowville in the extreme north, and 35.8° at Saint George in the extreme southwest. For July the mean is 75.5° at Salt Lake City, 69.5° at Snowville, and 83.1° at Saint George. The lowest temperature ever observed at any of the regular stations is 34° below zero, and the highest 115°. The snowfall is light, but in the mountains the winters are very severe, and the summits are capped with perpetual snow. The rainfall throughout the State is insufficient for the needs of agriculture, and irrigation is everywhere necessary. The average precipitation for the State is 12 inches. The greatest amount falls in the north central portion, the average precipitation at Salt Lake City being 16.2 inches. Elsewhere it is less than 10 inches, falling to 6 inches in the southwest.
Soil and Vegetation. The soil of the valleys, where it docs not hold injurious amounts of alkaline deposits, usually contains the elements of fertility, which render it very productive when irrigated. It is at best a sedimentary loam composed of sand and clay, but in some places it is rocky or gravelly. Where not irrigated by artificial canals or natural watercourses the country is arid and treeless, covered with sagebrush on the plains, though the higher slopes are grassy. To the southwest of the Great Salt Lake lies the wide, arid plain known as the Great Salt Lake, or Great American, Desert. For details of the flora and for fauna, see paragraphs under Rocky Mountains.
Geology and Minerals. The surface formations of the State are somewhat complicated and irregular in their outcrops. Ancient crystalline rocks appear as the core of the Uintah Mountains in the northeast. They are flanked by narrow outcrops of Jurassic and Cretaceous strata, south of which there is a broad area of Eocene formation. The great plateau forming the southeastern quarter of the State is almost wholly of Jurassic and Cretaceous age. The Wasatch Mountains present in their northern half a narrow ridge of Carboniferous rocks protruding through the Cretaceous and Tertiary strata, but their southern half is formed mainly of great masses of igneous rocks. The isolated ranges of western Utah are of Carboniferous and older Paleozoic formation, yet the basin-floor surrounding them is overlaid by sediment from Lake Bonneville (q.v.) , a Pleistocene lake whose remnants still remain in the Great Salt and Sevier lakes. The mineral wealth of Utah includes extensive coal deposits on the eastern slope of the Wasatch and ledges of iron ore in the southwest. Gold is found chiefly in the Oquirrh Range south of the Great Salt Lake, while silver occurs in considerable quantities in connection with the lead and copper ores which are abundant in many of the mountain ranges. Other important minerals found in the State are manganese, deposited in the Triassic sandstone of the eastern plateau, gypsum, rock salt and borax, sulphur, pumice, and asphaltum.
Mining. In 1901 the commercial value of the silver mined was $6,456,480—a decided gain over any preceding year. About two-thirds of this was obtained from lead ores, and the largest part of the remainder from copper ores. The value of the gold produced in 1901 was $3,090,200, which was also much larger than the output for any year excepting 1900. The gold is obtained from quartz mines. The production of lead for 1901, 49,870 short tons, was the largest output reached in any year, and over twice that for 1894. The State ranks third in this production. The output of coal has increased continuously in amount since 1890, being 1,322,614 short tons in 1901, or over three times the yield for the former year. From Carbon County is obtained 95 per cent. of the total product. The production of copper fluctuated about a low figure prior to 1898, in which year the output amounted to only 3,750,000 pounds. But there was a rapid increase following that year, the output in 1901 being 20,116,979 pounds. Increasing quantities are obtained from low-grade ores. The State ranks fifth in copper-mining. Salt is manufactured at Salt Lake, the yield in 1901 being 334,484 barrels, valued at $326,016. Limestone and sandstone, brick and tile, and Portland cement are products of some value.
Agriculture and Stock-Raising. Agriculture is the chief occupation. Utah was the first of the Rocky Mountain States to develop this industry, its success was dependent almost wholly upon irrigation, and it was the first State to demonstrate the possibilities of the irrigation system in the United States. The system has developed under conditions here not found elsewhere, and with much more satisfactory results to those who share its advantages. The planning and control of the system by the Mormon authorities made harmonious cooperation possible, and an economic distribution of the water without disputes over rights to its use. The land was divided into areas convenient for cultivation by a single household, so that there was a remarkable uniformity in the size of irrigated farms, and their average size was much less than for any other State. With the recent occupation of extensive unimproved areas, however, the average size of farms for the State has greatly increased. The average in 1860 was 30.2 acres, in 1880, 69.3 acres, and in 1900, 212.4 acres. The total farm area in 1900 (4,116,951 acres) was over three times that in 1890, and the improved area in 1900 (1,032,117 acres) was nearly twice that in 1890. In general, the northern counties have the largest farms. In 1900, 91.2 per cent. of the farms were owned by their operators.
The western half of the State belongs to the Great Basin, and nearly 90 per cent. of the irrigated land is within this basin. Salt Lake Valley in the north central part of the State contains a large part of the irrigated area. Almost the entire water supply is drawn from streams. Wells afford a very small amount. In 1899 there were 629,293 acres irrigated. Of the 686,374 acres of crops in that year, 537,588 acres were irrigated. Hay is the crop most extensively grown and also the most valuable crop, alfalfa being the principal variety. In 1899, 86.9 per cent. of the alfalfa was irrigated. Wheat and oats are the most widely grown cereals and both made large gains between 1890 and 1900. Of the area in oats 93 per cent. was irrigated, but only 57.4 per cent. of that in wheat. Much attention is given to vegetables, particularly potatoes and sugar-beets. The entire acreage of the latter and 94 per cent. of the former were irrigated. Prior to 1890 little attention was given to orchard fruits,
