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.

The Hot Springs are situated in a valley between two wooded, rocky ridges known as "West Mountain" and "Hot Springs Mountain." The water issues from vents in the old and gray hot-spring deposit, or tufa, that covers the basal slopes of Hot Springs Mountain east of Hot Springs Creek. This location is on the outer border of the mountain system. To the east the country falls away gently to the Ouachita River, and the city of Hot Springs has been built partly in the ravine and the intermontane basin to the north and partly in the eroded plateau lying south of the springs and outside of the mountain area. The mountain slopes are rocky, and are often ribbed with abrupt cliffs and rugged ledges with extensive slopes of talus. They are generally thickly mantled with a heavy forest growth of oak, pine, chestnut, and other common forest trees, and they support a more or less abundant undergrowth. The ravines are generally narrow and the streams swift running, but good exposures of the underlying rocks are seldom seen, owing to the thick forest that covers the slopes. There is an evident relation between the hard rocks and the hills and between the softer rocks and the valleys, although the streams do not accord with any definite geological structure, but flow in synclines, in eroded anticlines, and across the strike of the beds as well. Several gaps indicate old and now abandoned stream courses and show a prolonged period of adjustment, in which the streams shifted several times before reaching their present position. Although the springs are on the borders of these mountains, this location is not wholly outside of the mountain area, since the Trapp Mountain Range lies south of the Ouachita River, so that the springs are on the north side of a synclinal basin that forms an embayment between the main Ouachita system and a small east-and-west spur on the south. The region is well watered and well drained. In the immediate vicinity of Hot Springs the Hot Springs Creek and Gulpha Creek, both of which flow into the Ouachita River, drain the entire region, the former stream flowing due south and reaching the river 4 miles below the city.

The lower country near the springs, upon which a considerable part of the city is built, is a dissected plain in which broad plateau levels alternate with shallow drainage courses that are tributary to Hot Springs Creek.

The climate of the region is a mild one, lacking both the extreme heat of summer and the cold of winter. In the summer months the air is tempered by the breezes from the mountains, and in winter the average temperature is very slightly below that which prevails at New Orleans and other southern cities. Flowers and shrubs of semitropical character grow in the open air, but the occasional frosts of winter are so sharp that a strictly semitropical vegetation will not exist.