COLLECTING AREA OF HOT SPRINGS 285 



on and near the Ouachita River, and the areas of igneous rock at 

 Potash Sulphur Spring, Magnet Cove, and other near places, force 

 the suggestion upon one that the waters of the springs owe their 

 temperature to passing over hot rocks, or the vapor from such, in 

 some part of their underground course. The fact that these are 

 practically' the only hot springs within the Ouachita area, though there 

 are scores of cold springs issuing from the same formations and under 

 the same geologic relations, gives this suggestion great weight; but 

 inasmuch as some of the hot springs are said to be unusually radio- 

 active, there is the alternative suggestion that atomic decomposition 

 in igneous rocks (which may have lost their magmatic heat) is the 

 source of the high temperature of the water. 



I Recently a spring, said to have a temperature of 98° to 100° F., has been dis- 

 covered issuing from the Arkansas novacuUte in the bed of the Caddo River at Caddo 

 Gap, Montgomery County. 



