438 DESCRIPTIVE GEOLOGY. 



At the point of the projecting spur of the Wahsatch, just north of Salt 

 Lake City, a warm sulphur spring gushes out of the Wahsatch limestones, 

 sending down a little stream, some 6 feet wide, of sulphurous waters, into 

 the little arm of the lake called Hot Spring Lake. These waters, like most 

 of the springs around the lake, contain chloride of sodium as their principal 

 mineral ingredient. Between this point and the city is another warm spring 

 in the limestone, whose waters contain some sulphuretted hydrogen. At 

 this spring are baths, much used by the inhabitants. The following analy- 

 sis of its water, made by Dr. C. T. Jackson, is exposed in the bathing estab- 

 lishment: "Three ounces of water, evaporated to dryness, gave 8.25 grains 

 of solid matter. 



Carbonates of lime and magnesia 0.240 



Peroxide of iron , 0.040 



Lime 545 



Chlorine : 3.454 



Soda 2.877 



Magnesia .'J 0.370 



Sulphuric acid *. 0.703 



. 8.229 



"It is slightly charged with sulphuretted hydrogen and carbonic acid." 

 It is interesting to note the occurrence of these hot springs with those 

 at Ogden and in Bear River Valley, occupying a line just west of the foot 

 of the mountains, which is approximately that of the great system of faults 

 which have thrown down the western side of the range, and nearly parallel 

 with the line of volcanic outbursts on the eastern flanks. 



Salt Lake City itself is situated upon the gently-sloping plains of 

 Quaternary gravel, just at the base of one ,of the broader and .more promi- 

 nent, though by no means the highest, of the old lake-terraces. It is about 

 7 miles distant from the lake, which, owing to the flatness of the shores, 

 cannot be seen from the level of the city. From the terrace above the city, 

 however, a view is obtained to the westward over the lake to the mountain- 



