420 DESCRIPTIVE GEOLOGY. 



SECTION V. 



REGION NORTH OP SALT LAKE. 



BY AENOLD HAGUE. 



Promontoey Uplift. — To the west of the northern portion of the Wah- 

 satch Eange lies a broad Quaternary plain, in part occupied by the shallow 

 waters of an arm of Salt Lake, known as Bear River Bay, and in part by the 

 valley of the Bear and Malade Rivers. Along the shores of the bay, and in 

 the deeper cuts of these rivers, are exposed the fine mud deposits of the 

 Lower Quaternary, which, over the greater part of the surface, are concealed 

 by the more recent detrital material of the Upper Quaternary. Beyond 

 the limits of the map, the valley of the Malade extends in a northerly 

 direction, while Bear River, as already mentioned, has broken through the 

 range at the "Gates", coming from the region north of Cache Valley, in a 

 general southwesterly course, after having flowed from the Uinta Range 

 through the Upper Bear River Valley, about 150 miles nearly due north. 

 On the west side of the Malade River Valley, along the northern limits of 

 the map, low rounded hills of limestone rise up above the Quaternary beds, 

 presenting a broken undulating surface, and extending westward to the 

 valley of Blue Creek. These limestone hills or ridges show a number of 

 synclinal and anticlinal folds, with gentle dips, which can be traced from 

 the Promontory Mountains nearly to Bear River. The first ridge to the 

 eastward of Blue Creek has an inclination to the east, while the second 

 ridge dips westward, forming a synclinal, followed by a second anticlinal 

 fold to the eastward, the beds dipping under the valley, while in the small 

 isolated hill to the west of Corinne, known as Little Mountain, the beds dip 

 to the north at an angle of 18°. Th© northern end of these hills was not 

 visited by our parties; but there would seem to be little doubt that they 

 belong to the same horizon as the more southern hills, which have been 

 referred to the Wahsatch limestone, from their close structural and litho- 

 logical relations to the heavy limestone-beds of the Promontory Mountains. 



This range extends from the northern limit of the map about 45 miles to 

 the southward, forming a rocky promontory, which divides the two northern 



