82 HOT SPRINGS, ARKANSAS. 



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 

 wholty 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 ^he immediate vicinity of 

 Hot Springs the Hot Springs Creek and Gulpna 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 tbat 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, r ^nd 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. 



ROCKS OF THE DISTRICT. 



The rocks seen about the Hot Springs are chiefly of sedimentary 

 origin and were formed beneath the waters of a Paleozoic sea. They 

 occur in well-defined formations, which were folded when the moun- 

 tains of the region were formed by the compressive stresses of earth 

 movements, and these folds have subsequently been eroded by ordinary 

 atmospheric agencies. These rocks are cut by a few narrow, insig- 

 nificant dikes of igneous rock, which are supposedly connected with 

 the large masses of granite and other igneous rocks now seen at 

 Magnet Cove and Potash Sulphur Springs. In addition to the rocks 

 mentioned there is a considerable area of dark-gray and porous tra- 

 vertine, or calcareous tufa, formed by the Hot Springs. 



The sedimentary rocks seen in the vicinity of the Hot Springs con- 

 sist of shales, sandstones, a few beds of impure limestone, and the 

 rock called novaculite. This last-named rock, of which the well-known 

 Arkansas whetstones are made, is the most conspicuous and important 

 rock in the locality. It is the typical rock of central Arkansas, and, 

 though found over a large area, the material pure enough to be used 

 for whetstones is confined to the vicinity of the Hot Springs. It is 

 this rock that has, by reason of its hardness and its resistance to erosion, 

 made the mountains about the springs, and it forms the cliffs and 

 prominent ledges seen in the district. The bedded rocks form a series 



