01U!i;UT .l POCATELLO TO SALT LAKE CITY. 379 



The largest ancient delta is that of the Bear river, bnt those formed 

 by some of the smaller streams are more symmetrical. That built by 

 Logan river has the form of a semicircular terrace projecting into the 

 valley its upper surface constituting an obtuse cone whose apex is at 

 the mouth of the mountain gorge whence issues the river. By subse- 

 quent action the river has divided the terrace into two parts, and there 

 are other delta terraces at lower levels. Upon these terraces stands 

 the city of Logan on the east side of the valley Near the base of the 

 mountain the Logan delta is traversed by a fault scarp, feet (2 m.) 

 high Cache valley lies chiefly in Utah and contains a large number 

 of thriving settlements founded by the Mormons. Their chief Indus! ry 

 i^ agriculture, and this is carried on by the aid of artificial irrigation, 

 the waters of the streams being diverted from their channels and carried 

 by ditches to the farming land. The principal town, Logan, has a pop 



ulation of 4,665. 



Northward from Red Rock pass the railroad traverses tor several 

 miles a plain little below the level of the pass ami then descends to the 

 jnunediat e valley of Bear river, which is followed to the " Gates*' and be- 

 yond (Plate VI). The passage opened by the river through the western 

 mountain ridge exhibits a nucleus of Paleozoic limestone, against which 

 on each side rest Humboldt beds. These last are upturned to 46° at 

 the east and to 15° at the west, and air in turn overlain by marls, sands 

 and tufas of Bonneville date. The erosion of the river gorge was pre- 

 Boiraeville, and its sides are sheeted by calcareous tufa to a depth of 

 several feet. In sections opened by the railway the tufa is seen to have 

 been deposited in two or more sheets separated by bodies of talus 

 believed to represent one or more inter -lacustrine epochs, llerea great 

 engineering work is in progress. By a dam near the head of the gorge 

 the water of the river is diverted into two canals, which have been car- 

 ried, partly through tunnels, along the walls of the gorge ami then led 

 out along the upper benches of the plain to the west. By their aid a 

 large tract of desert land will be reclaimed to agriculture. 



After passing through "The Gates" the road runs southward, 

 between the steeper mountain slope on the left and the valley of Rear 

 river on the right. A tine view is obtained, across the valley, of the 

 Promontory range, which forms its western boundary. -N> miles (65 

 km.) away." This range is so called because it extends into Great Salt 

 lake, dividing its northern portion into two great bays. 



The road passes the Mormon towns of Willard, Box Elder, and Brig- 

 ham, resting on the gentler slopes of the valley and surrounded by 

 fields Irrigated by waters from the mountain streams issuing from 

 ravines behind them. Beyond Brigham the road passes round a pro- 

 jecting point of the Wasatch mountains, opposite the north end of 

 Great Sail lake, to Utah (Bonneville) Hot springs, which issue from 



