plain, from whence it either re-enters the river lower down in its course, or finds its way into the depression. The Salton Marsh at present acts as the catchment basin for the waters draining from the east side of the San Jacinto range, Carizoo Creek, and a part of the San Bernardino Mountain range, and in times of extreme high waters as a reservoir for the excess in the Colorado River. In the month of June, 1891, a steady flow of water entered the depression from the southeast and continued to the northwest uninterruptedly until an area 30 miles long and averaging 10 miles in width was covered to a depth of 6 feet, measured at the end of the Salton Salt Works branch track. When first examined the water showed a density of 7° Baumé, which gradually increased to 25° Baumé. The mother liquor used in making salt at the New Liverpool works usually shows a density of 27° Baumé. This salt water gave rise to the idea that the waters from the gulf had made an inroad through some underground channel, and to prove the source and possible permanency of these waters several investigating parties were sent out. No such previous incursion had been witnessed by the settlers, but inquiry proved that a similar lake existed here in 1849. Finally one of the parties showed that the Colorado River was the source, and then the question was brought to the attention of the State Mining Bureau to investigate as to the probability of the permanency of the lake and its probable effect on the climate of the surrounding country. The Colorado in its great length accumulates a large amount of sediment, from 0.1 to 0.4 per cent per gallon, and after this has been deposited the water on evaporation is found to contain 0.14 grammes solid residue, consisting largely of sulphate of soda and chloride of sodium. With the sediment the river is all the time building up its flood plain, and it may not be out of place to recall the general laws that govern the actions of streams while depositing the solid matter they carry in suspension. Currents bearing sediments deposit a large percentage as soon as their velocity is checked in the least, but pick up deposited sediments again as soon as the current is increased. Thus a variable current is depositing at one point while eroding deposits at other points.