June 26, 1884] 



NA TURE 



197 



and I am always expecting to see it go. At its feet cluster 

 our bed of Cycads, the latter shaded by young Oreodoxas 

 and Caryotas, and with the margin of the bed fringed by 

 the long feathered leaves, plume-like, of Phcenix rupicola. 

 Here and there gleams of silver catch the eye, as the sun, 

 striking on the ornamental stretches of water, glances 

 through the foliage. To the left another member of that 

 beautiful section of the Rubiacea — the Naudece — occupies 

 a prominent place, its stem the home of the handsome 

 blossoms of Vanda teres. The pretty marble pillar and 

 urn to the memory of Col. Kyd is seen through the 

 branches. From it roads lead to the principal landing- 

 stage bordered by Oreodoxas, mahoganies, and our only 

 attempt at ribbon gardening, long lines of Acalyphas, &c. 

 Another road, straight for nearly, if not quite, half a mile 

 to one of the exits, has an avenue ofPofyalthia longifolia, 

 sacred to the Hindoos, and groups of Betle palms ; then 

 of Oreodoxas, and lastly of Inga Saman. We have great 

 difficulty with the Oreodoxas on account of a beetle 

 that lays its eggs in the terminal buds. Still another 

 road leads to the Orchid House bordered by clumps of 

 graceful bamboos. In the house we generally manage to 

 have a pretty show, and its neighbourhood in the proper 

 season is gay with the blossoms of A mherstia Gustavia, 

 Thunbergia Napoleona, &c. Magnolia grand/flora is 

 flowering with us just now. What a glorious flower it is ! 

 Yesterday and the day before there came down on us one 

 of the sudden miniature cyclones that we are so liable to 

 have at the approach of the change of the monsoon. It 

 blew, rained, and hailed tremendously. The trees tossed 

 their arms and wailed, poor things, with such effect that 

 their branches everywhere broke and strewed the ground. 

 However only one small mahogany fell. It was quite 

 cold, and the rain froze, as it was falling, into lumps as big 

 as marbles." 



THE EXTINCT LAKES OF THE ORE A T BASIN 



THE Great Basin of North America presents the most 

 singular contrasts of scenery to the regions that sur- 

 round it. East of it rise the dark pine-covered heights 

 of the Rocky Mountain system, with the high, bare, 

 grassy prairies beyond them. To the west tower the 

 more serrated scarps of the Sierra Nevada, with the steep 

 Pacific slope on the other side. The traveller who enters 

 the Basin, and passes beyond the marginal tracts where, 

 with the aid of water from the neighbouring mountains, 

 human industry has made the deseit to blossom as the 

 rose, soon finds himself in an arid climate and an almost 

 lifeless desert. The rains that fall on the encircling 

 mountains feed some streams that pour their waters into 

 the Basin, but out of it no stream emerges. All the water 

 is evaporated ; and it would seem that at present even 

 more is evaporated than is received, and that consequently 

 the various lakes are diminishing. The Great Salt Lake 

 is conspicuously less than it was a few years ago. Even 

 within the short time that this remarkable region has 

 been known, distinct oscillations in the level of the lake 

 have been recorded. There are evidently cycles of greater 

 and less precipitation, and consequently of higher and lower 

 levels in the lakes of the Basin, though we are not yet in 

 possession of sufficient data to estimate the extent and 

 recurrence of these fluctuations. 



It is now well known that oscillations of the most 

 gigantic kind have taken place during past time in the 

 level and condition of the waters of the Great Basin. 

 The terraces of the Great Salt Lake afford striking 

 evidence that this vast sheet of water was once some- 

 where about 1000 feet higher in level, and had then an 

 outflow by a northern pass into the lava deserts through 

 which the canons of the Snake River and its tributaries 

 wind their way towards the Pacific. Mr. Clarence King, 

 Mr. Gilbert, and their associates in the Survey of the 40th 

 Parallel, threw a flood of light upon the early history of 



the lake and the climatic changes of which its deposits 

 have preserved a record. They showed that the present 

 Great Salt Lake is only one of several shrunken sheets of 

 water, the former areas of which can still be accurately 

 traced by the terraces they have left along their ancient 

 margins. To one of the largest of these vanished lakes the 

 name of the French explorer Lahontan has been given. The 

 geologists of the 40th Parallel Survey were able to portray 

 its outlines on a map, and to offer material for a compari- 

 son between it and the former still larger reservoir of which 

 the present Great Salt Lake is only a relic. The United 

 States Geological Survey has since begun the more de- 

 tailed investigation of the region, so that ere long we shall 

 be in possession of data for a better solution of some of 

 the man)- problems which the phenomena of the Great 

 Basin present. In the meantime Mr. J. C. Russell, who 

 has been intrusted with this work, has written an inter- 

 esting and suggestive preliminary report of his labours. 



The average rainfall of the area of the Great Basin 

 is probably not more than 12 or 15 inches. In the 

 more desert tracts it may not exceed 4 inches, though in 

 the valleys on the borders of the Basin it may rise to 20 

 or 30 inches. The rain falls chiefly in autumn and 

 winter, consequently many of the streams only flow during 

 the rainy season, and for most of the year present dry 

 channels. Even of the perennial water-courses, the larger 

 part of their discharge is crowded into a brief space 

 towards the end of the rainy season. Most of the streams 

 diminish in volume as they descend into the valleys, and 

 many of them disappear altogether as they wander across 

 the blazing thirsty desert. Loaded with sediment, and 

 more or less bitter with saline and alkaline solutions, they 

 do little to redeem the lifelessness of these wastes. 



Over the lower parts of the surface of the Basin are 

 scattered numerous sheets of water. Where these have 

 an outflow to lower levels they are fresh, as in the examples 

 of Bear Lake, Utah Lake, and Tahoe Lake. But the great 

 majority have no outflow. Some of them are merely 

 temporary sheets of shallow water, appearing after a 

 stormy night, and vanishing again beneath the next noon- 

 day sun, or gathering during the rainy season, and dis- 

 appearing in summer. Yet in some cases these transient 

 lakes cover an area of 100 square miles or more. When 

 they dry up, they leave behind them hard smooth plains of 

 grayish mud, that crack up under the burning sun, and then 

 look like a broken mosaic of marble. Of the permanent lakes 

 the largest is the Great Salt Lake. It is also by much the 

 most saline. Though all of them are more or less charged 

 with alkaline and saline solutions, the percentage of 

 these impurities is in some cases not so great as to pre- 

 vent the water from being drunk by animals, or even on 

 an emergency by man himself. Nothing in the physics of 

 the Basin is more remarkable than the great diversity in 

 the amount and nature of the mineral substances in 

 solution in the lakes. 



The vanished sheet of water, or " fossil lake," as the 

 American surveyors call it, known as Lake Lahontan, lay 

 chiefly in the north-west part of Nevada, but extended 

 also into California. In outline it was exceptionally ir- 

 regular, being composed of a number of almost detached 

 strips and basins connected by narrow straits, and some- 

 times separated only by narrow ridges. It inclosed a 

 rugged mountainous island 126 miles long from north to 

 south, and 50 miles broad, which contained two lakes, 

 neither of them apparently overflowing into the main 

 lake. The Central Pacific Railroad passes for 165 miles 

 through thejdried-up bed of Lake Lahontan. From the 

 windows of the car one can look out upon the ancient 

 clay floor of the lake and mark the marginal terraces 

 winding with almost artificial precision along the bases of 

 the hills. The larger basins, which were formerly united 

 into one continuous sheet of water, still hold lakes, all of 

 which are more or less saline and alkaline, but they are 

 far from being such concentrated brines as might be 



