Such a saltwater saucer of fresh water is maintained full to overflowing by the rainfall, and owing to the frictional resistance of the sand and to capillary action and the fact that a given column of fresh water is balanced by a shorter column of sea water, the fresh water never sinks to the mean sea-level unless artificially abstracted.
In process of time some of these banks, as in the case of Venice, raised themselves above the level of the water and became the true shore-line, while behind them lay large surfaces of water, called lagoons, formed partly by the fresh water brought down by the rivers, partly by the salt-water tide which found its way in by the channels of the river mouths.
Large coarse algae, such, for instance, as the Fucaceae and Laminariae, do not readily adhere to paper, and require soaking for some time in fresh water before being pressed.
These are opposite to the large estuaries of the Queensland rivers, and might be thought to have been caused by fresh water from the land.
On the upheaval of such rocks above the sea-level, fresh water from rainfall began to flow over their exposed surfaces, and, so far as the strata were permeable, to lie in their interstices upon the salt water.
The springs of fresh water that bubble up among the keys of the S.
Inland from Manila Bay, is Laguna de Bay, the largest body of fresh water in the Philippines.
Characteristic of fresh water has yet been observed in it.
Small springs of fresh water are frequent and there are 'several shallow lakes or pans - flat bottomed depressions with no outlet.
Although many plants typical of fresh water are able to grow also in brackish water, there are only a few species which appear to be quite confined to the latter habitats in this country.