There has been a long history of inland seas filling the Salton Trough. As recently
as 500 A.D., the Salton Sea (referred to as Cahuilla Lake) was ten times larger
(at about 3,900 square miles or the size of the state of Delaware) than it is at present.
Scientists know this because of "bath tub rings" or paleoshorelines left on the rocks of the surrounding
mountains. In the past, the Salton Trough has held a great deal of glacial melt from the last Ice Age.
At its zenith, Cahuilla Lake was an enormously rich ecosystem. Fossil remains show
that it was probably a fresh water lake. Over time, it too would have accumulated
salinity, due to evaporation.
This is image of the Pleistocene lakes in the western United States. Lake Cahuilla
(bottom left) is labeled.
The size of the present day Salton Sea is shown in black within Lake Cahuilla.
