A level tract where the ground-water surface coincides with the surface of the ground is a swamp or marsh.
It should be clearly recognized that oxidizing processes are not limited to the zone above the ground-water level.
The ground-water surface is the name given the upper surface of ground water, the level below which all rocks are saturated.
The top surface of this zone is called the water table, or the ground-water level.
Unfavorable to all field works on account of ground-water and floods, and not thick enough for cave shelters.
The oil and gas distillates migrate upward under gas pressure and under pressure of the ground-water.
The oxide zone of these deposits has no close relation to the present topography or to the present ground-water level.
Gypsum is fairly soluble in ground-water, and sink-holes and solution cavities are often developed in gypsum deposits.
In a humid climate the larger ravines through which the run-off flows soon descend below the ground-water surface.
The low state of the rivers was an index of a low level of the ground-water.