TEERACE MOUNTAIl^S. 427 



beautifully shown. Seven well-defined, sharply-cut benches, several feet 

 wide, were counted, one above the other, on the sides of the hard rock. 

 Probably no locality in the region of Salt Lake affords a better opportunity 

 for observing the broader and more permanent lake-terraces which mark 

 the changes of level of the earlier bodies of water. 



Terkace Mountains. — In their physical aspect, the Terrace Mountains 

 bear a marked resemblance to the other ranges of the Salt Lake Basin, 

 especially to the Promontory Mountains on the opposite side of the lake. 

 They measure about 20 miles in length by 4 to 6 in width, the culminating 

 peak reaching 2,700 feet above the present water-level. Tangent Peak, 

 the highest point in the mountains, affords on a clear day a most striking view 

 of the arid gray desert and the blue lake stretching away to the southward 

 and eastward as far as the eye can reach. The eastern horizon is bounded by 

 a grand panoramic view, of over a hundred miles in length, of the Wahsatch 

 Range, while to the westward the East Humboldt Range stands out in nearly 

 equal distinctness, but with a more rugged and varied outline. The mass 

 of these mountains, as far as visited, appears to be made up of beds of the 

 Wahsatch limestone. The summit of Tangent Peak is occupied by a bluish- 

 gray limestone, below which occurs a dark, siliceous, cherty band, in turn 

 underlaid by dark-gray limestones. The recorded strike is north 16° east, 

 with a gentle dip to the northwest. No fossils were found, except fragments 

 of coral stems, too poor for identification. Just north of Tangent Peak, 

 the spurs fall off somewhat abruptly, and a low saddle, with both east and 

 west canons, or valleys, separates the mountains into two distinct ridges. 

 Both of these canons are marked by broad, shallow basins, with gentle 

 slopes between the limestone ridges. In both valleys, there is a very con- 

 siderable development of horizontal Tertiary beds, extending nearly to the 

 summit of the divide, which have escaped erosion and concealment beneath 

 the Quaternary deposits. These beds resemble the fine sands, reddish 

 ■gravels, and marls which form the Humboldt Pliocene beds of Eastern 

 Nevada, and have been referred to the same horizon. 



The terrace-lines, which form so characteristic a feature of the basin, 

 are so prominent and well defined along the slopes and foot-hills as to have 

 given the name to this range of mountains. They are remarkably well 

 shown on the Tertiary strata, where seven broad, nearly level, benches may 



