It is due to the narrowing of the Gulf of California forcing the tides into close quarters, and its violence is augmented by collision with the equally furious current of the Colorado.

The battle between this tidal wave and the Colorado continues for many miles, till at last the sea tide gradually loses its power and succumbs to the flood of the river.* The latter falls at the mouth, according to Ives, about thirty feet in a few hours after the ebb begins.

The shallower the water as the tide rushes in against the ebb, the angrier the wave becomes, sometimes reaching a height of ten or twelve feet.
* The tide ascends thirty-seven miles.

Lowest stage of water about three feet, average six feet, and highest about twenty feet.
At Robinson's Landing, a mere mud flat, a camp was established and preparations made for the voyage to the extreme limit of navigation.
The parts of the steamer were put ashore and a suitable spot selected whereon to set her up.

The high tides were over for a month, and the mud began to dry, enabling the party to pitch their tents.