THE OVERLAND ROUTE OGDEN TO SAN FRANCISCO. 151 



mam 



Promontory 



tallied cliiefly for purposes of railroad operation. 

 Point. U^ock and gravel for building tho ombankniont across 

 Elevation 4,217 feet, the lake werc obtained at several places along the 



Omaha 1.023 miles. * , i ^ ii • * rr^i i t • m 



south end of the point, ine rock exposed m rail- 

 road cuts and quarries here is a black slate, which weathei-s rusty 



and brown. 



Just west of Promontory Point station, on the north side of the 

 track, is a pond cut off from the lake by the railroad embankment. 

 At times of high water in the lake this reservoir fills by percolation 



^.. ...^ embankment 



centrated to a brine by evaporation. The deep pink color of the 

 brine is a phenomenon that appears in salt ponds generally when a 

 certahi concentration is reached. In the salt ponds of San Francisco 

 Bay this color is due to a certain bacillus which lives in saturated 

 brines and also in the heaps of salt as it is piled for drainage and 

 shipment. Prohibitive to life as such an environment might be con- 

 sidered, strong natural brines are, in fact, inhabited by a number of 

 minute organisms^-animals as well as plants. The pink color dis- 

 appears in Avintcr or when fresh water is introduced into the pond. 

 The railroad compan}^ has done "some experimental work on preserv- 

 ing piles and ties by soaking them in this pond. 



Bej^ond the pond the track follows the lake shore along the south 



mile 



group 



od Saline. 



Looldng a little east of south from Promontory Point, one can see 

 on the south shore of Great Salt Lake the town of Garfield, the con- 

 centrating mills of the Utah Copper Co., and the copper smelter of 

 the Garfield Smelting Co. A long column of smoke may usually be 

 seen trailing away over the mountains from the smelter stack. These 



plants were constructed a few years ago to treat copper ores from 

 Bingham Canyon, a short distance to the south, in the Oquirrh Ptange, 

 and the town of Garfield was established to furnish accommodations 

 for the men employed at the miUs and smelter. The two mills of 

 the Utah Copper Co. are among the largest concentratuig plants in the 

 world and together are capable of treating over 20,000 tons of. ore 

 daily. The ore treated contains an average of about 1.5 per cent of 

 copper in the form of sulphides. 



At' the semaphore marked 754.5 miles the railroad runs out on 

 the fiU across the west arm of the lake. Large excavations near by 

 are in the ^^ gravel" that was at first used in constructuig the fill. 

 This ^'graveP' is of a very unusual character. If examined closely, 

 preferably with a magnifying glass, it is found to consist of smoothly 

 rounded, opaque grains, not like ordinary sand grains. Tliese are 

 kno\%^i as oolites, the word oolite meaning hterally fish-egg stone or 



