THE OVERLAND KOUTE COUNCIL BLFFFS TO OGDEn' 



99 



in comparatively recent geologic time and that has an interesting 



origin. 



[For continuation of itinerary to San Francisco, see p. 148.] 



Oxford and Downey the railroad traverses 

 the Red Rock outlet channel, one of the 

 stations, Swan Lake, being within the 

 channel. The modern streamlets, flow- 

 ing from neighboring hills, have brought 

 down enough gravel and sand to build 

 alkivial dams and have thus obstructed 

 the drainage of the old ri^'e^ bed, so that 

 it now contains a series of ponds and 

 marshes. 



In quality of water and in temperature 

 Lake Bonne\ille was as well fitted for 

 abundant and varied life as the Bear 

 Lake of to-day, and though the only re- 

 mains yet found in its sediments are 

 fresh-water shells, we need not doubt 

 that its waters teemed with fish. We 

 niay confidently picture its bordering 

 marshes as fields of verdure and its bolder 

 shores as forest clad; and we may less 

 confidently imagine primitive man as a 

 denizen of its shores and an eyewitness 

 of the spectacular deluge when its earthen 

 barrier was burst. 



The only permanent animal inhabitant 

 of Great Salt Lake is a tiny ''brine 

 shrimp, " a third of an inch in length. A 

 more conspicuous temporary resident is a 

 minute fly which passes its larval stage in 

 the water, and when its transformation 

 takes place leaves behind it the discarded 

 skin. These flies are so numerous in their 

 season that even the passing tourist should 

 feel grateful that they do not bite. Their 

 brown exuviae darken the water edge and 

 often sully broad belts of the lake surface. 

 More decorative denizens are gulls and 

 pelicans, which find safe nesting groimd 

 on some of the smaller islands. There 

 are no shoal-water plants, and the salt 

 spray of the beach is fatal to all land 



Vegetation along the shores. 



^Tien the lake is low its salt is segre- 

 gated and deposited in shallow lagoons at 

 Its margin, to be redissolved when the 

 ^ater rises. Each autumn, as the water 

 cools, deposits of hydrated sodium mil- 

 pbate (Glauber's salt) coat piles and other 



a long island, and at the Bonneville stage fixed objects near the water surface, and 

 as a chain of smaller islands. Between the deposits increase as the temperature 



falls. In the depth of \vinter large masses 

 of this salt may be seen along the embank- 

 ments and trestles of the Lucin cut-off. 

 Calcium carbonate, the mineral consti- 

 tuting limestone, travertine, and chalk, 

 is continuously and permanently sepa- 

 rated from the water, which is unable to 

 retain that which is brought to it by tlie 



Along the shores it forms minute 

 balls, which together constitute sand, a 

 sand quite distinct from the siliceous sand 

 of ordinary beaches. 



Man makes little use of the lake. On 

 its shores there are neither fisheries nor 

 ports, and commerce finds it an impedi- 

 ment rather than an aid. Its deposits of 

 Glauber's salt, which it offers for the 



nvers. 



gathering, are 



neglected because 

 is small and is ch< 



the 





met in other ways. Its common salt is 

 harv^ested with great economy of effort, 

 for impurities are easily excluded and 

 the work of evaporation is performed by 

 the sun. The present annual output of 

 40,000 tons must be multiplied fivefold be- 

 fore it can ci>mmence to weaken the brine. 

 For the rest man is content to resort to 

 its shore for bathing and to realize a new 

 sensation as he floats upon its surface. 



^ Most of the rocks in the Wasatch 

 Rano-e were laid down as sand and mud 

 on the bottom of the ancient sea, -whero 

 they became compacted and hardened 

 into sandstone, ehale, and limestone. 

 The sea bottom eventually became land. 

 As mother earth has aged her skin has 

 cracked and wrinkled. In the Utah- 

 Nevada region many long cracks were 

 formed and the rocks on one side or the 

 other were moved slowly upward or down- 

 ward, forming long ridges along the 

 cracks, steep on one side and genti}- slop- 

 ing on the other. Such breaks in the 

 earth's cru?t are called faults. A fault 

 may be a few feet or hundreds of miles 

 lon^ and the distance which the rock 



on one side slip past th( 

 may range from a fraction 



