562 E. HUNTINGTON SOLAR HYPOTHESIS OF CLIMATIC CHANGES 



existence of a system of well marked lake terraces. They have not been ex- 

 amined. 



''Railroad Valley, Nevada. — By repeated anero'id measurement the highest 

 terrace is 155 feet above the present playa. It is double, with the lower strand 

 about 3 feet below the upper. There are well marked lower terraces at about 

 120, 105, and 65 feet, the last being especially well developed. Minor strands 

 have been distinguished at about 95, 90, 85, 75, CO, and 50 feet. 



''The Mono Basin, California. — Russell" reports a high terrace about 680 

 feet above the present lake and a complex system of lower terraces and strands 

 which he does not describe in detail. 



"The Salton Basin, California. — The phenomena in this basin appear to have 

 been complicated by the occasional inflow of the Colorado River, with the con- 

 sequent filling of the basin. The present Salton Sea is due to such an inflow, 

 which was stopped artificially before the basin became full. There is one high 

 terrace at about the level of overflow into the Gulf of California, and below 

 this an extensive series of recessional strands.^^ 



"The Otero Basin, New Mexico. — Huntington " reports several high terraces 

 between 200 and 280 feet above the present playa and three recent strands at 

 4, 20, and 60 feet, the 60-foot strand being somewhat doubtful. 



"The Estancia Basin, New Mexico. — Meinzer" reports a highest terrace al- 

 most 150 feet above the present playa and a complex system of lower terraces 

 and strands, not described in detail. 



"The Encino Basin, New Mexico. — Meinzer ^" reports a high terrace at 60 feet 

 above the present playa, with some evidence of a temporary lake stage still 

 higher. No lower strands were found. 



"Las Playas Valley, New Mexico. — Huntington '^^ reports at least one strand, 

 the wave-bar which forms the Los Animas 'Dam.' " 



A little study of the map shows that the basins described by Free as 

 containing straces of ancient lakes are found in all parts of the area 

 shaded black on figures 16 and 17. They do not occur in any region 

 where the rainfall at present decreases during periods of many sun-spots. 

 Much more important than this, however^ is their striking evidence of 

 the great complexity of the climatic history of this region during post- 

 Glacial times. One or two of the oldest, most denuded strands may per- 

 haps antedate the last Glacial period. The freshness of the others, how- 

 ever, and the fact that they do not appear to have been covered by water 

 since they were formed indicates that they are of post-Glacial origin. 

 The sharpness of the details of some of the smaller strands near the bot- 

 tom indicates that they can not be of any great age — certainly not more 

 than one or two thousand years, and perhaps only a few hundred. The 



11 U. S. Geological Survey, Eighth Annual Report 1889, pp. 269-394. 



12 For details the reader is referred to MacDougal and others : The Salton Sea. Car- 

 negie Institution Publication 193, 1914. 



" Carnegie Institution Publication 192, 1914, pp. 39-40. 



i*U. S. Geological Survey, Water Supply Paper 275, 1911, pp. 19-23. 



i^Loc. cit., pp. 77-78. 



WLoc. elt., p. 70. 



