RECENTLY DISCOVERED HOT SPRINGS IN ARKANSAS 273 



easily forded where the springs issue, it seems remarkable that they 

 did not attract the attention of someone long ago. 



Caddo Mountain is one of the numerous east-west ridges that 

 constitute the Ouachita Mountains of west-central Arkansas. 

 Its height in the vicinity of the gap is 1,250 feet above sea-level, 

 and 600 feet above the stream level. As with all the other ridges 

 of the area, the rocks of this one have been disturbed by folding, 

 and, in addition to the folding, they have been faulted at the gap; 

 and like most of the other ridges, including the one from which the 

 springs of Hot Springs issue, the rocks are of the siliceous type 

 known as novaculite. 



At Caddo Gap, the rocks are on edge, and strike north 80 degrees 

 east, across the stream. They are here intersected by a thrust 

 fault, as shown in Fig. 2, with an east- west strike. 



°V 



Fig. 2. — Showing the geological section and the rock structure at Caddo Gap. 

 Also, the location of the thermal springs. 5, Stanley shale (Carboniferous); 4. 

 Arkansas novaculite (age undetermined); 3, Missouri Mountain slate (age undeter- 

 mined); 2, Bigfork chert (Ordovician); 1, Polk Creek shale (Ordovician); ss, Thermal 

 springs. 



Two springs are known, and their waters rise between the verti- 

 cal beds of novaculite. Possibly there are others that have not 

 yet been detected. At the time of discovery, all the water of the 

 springs issued below the stream level, but the points of emergence 

 have in part been closed with cement, so that some of the water 

 now issues from the west bank of the creek. For convenience, 

 the springs are here spoken of as the north and the south spring. 

 The surface of the north spring stands about 15 inches and that of 

 the south spring about 10 inches above the surface of the creek at 

 average stage. 



The north spring is about 40 feet south of the fault, and the 

 south one 25 feet farther. The temperatures of the two springs, 

 on July 2, 1910, as determined with a physician's thermometer, 



