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.

In the geological sketch already given the rocks from which the hot waters issue are described as sandstones and shales of Lower Silurian age, occurring in sharply compressed folds. The hot waters issue from the sandstones seen well exposed back of the superintendent's office and near the music pavilion, and from the overlying shales in the area west of the pavilion. These rocks form part of a steeply dipping anticline plunging beneath the surface toward the southwest. It may be compared to the partly buried prow of an upturned boat. The rocks arch around the mountain slopes, the different beds being revealed very much as the scales of an onion bulb are exposed when it is partly cut into. While the rocks are flexed into this great curve, the great and thick beds of hard sandstone and conglomerate were cracked while being flexed, and little slips and breaks occur. The smaller cracks form a network of fractures, which in some places are seen to be filed with white quartz. The princial springs are arranged along a line running about NNE., or parallel to the axis of the fold forming Hot Springs Mountain. This line is believed to be a fissure corresponding to a fracture of the northwest fold, a fault fissure. Springs are common along such fractures in the novaculite region of Arkansas, and there is no reason to believe there is anything unusual in this one. The source of heat is discussed elsewhere.