HOT SPRINGS Analyses of the Waters of The Hot Springs of Arkansas Geological Sketch of Hot Springs, Arkansas

GEOLOGICAL SKETCH OF THE HOT SPRINGS DISTRICT, ARKANSAS.

Central Arkansas consists of a low-lying, nearly level eastern portion, and a western hilly or mountainous region. The first region extends from the Mississippi River westward to Little Rock, Benton, and Malvern. The hilly country of the Ouachita Mountain system begins just west of the St. Louis, Iron Mountain & Southern Railroad, where it has a width of 36 miles, and extends westward, gradually narrowing as it approaches Oklahoma. The eastern level country is part of the Tertiary Mississippi Valley region. The western hilly country consists of a central complex of hills, flanked by sharp spurs and ridges, which extend outward into a much lower country of slight relief. This hilly country is dignified by the name of the "Ouachita Mountain system," the ridges rising gradually in elevation westward. Near the Oklahoma line the general level of the intermontane plain is 1,000 feet above tide and the crests of some of the ridges attain elevations above 2,500 feet. Near Hot Springs the mountain area seldom attains an elevation of more than 1,200 feet above the sea, or 600 feet above the surrounding country, yet, when seen from the lower country about it the hills rise so abruptly that they appear to deserve their designation. The mountains near the Hot Springs are particularly impressive, and the local summits have received special designations, as "West Mountain" "Indian Mountain," etc. These mountains have been grouped together by some writers under the name of the "Ozark system," but they have been more fittingly christened the "Zigzag" Range by Prof. Branner, of the State geological survey. This range has an extreme length of 25 miles and a width of 6 to 8 miles. The general trend of the ridges is almost at right angles to the system. These ridges are narrow and sharp, with a height of 500 to 600 feet, and they are particularly numerous in the vicinity of the Hot Springs.