The term "rock layer" is correct and usable in written English.
For example, "Geologists believe that the region has several different rock layers."
Aquifer, in hydrology, rock layer that contains water and releases it in appreciable amounts.
The thin surface rock layer surrounding the mantle is the crust, whose lower boundary is called the Mohorovičić discontinuity.
In the same rock layer, Dr. Olsen and his colleagues found a high concentration of fern spores -- considered an indicator of a major disruption in the environment.
Dr. Christensen said the pebbles must have come from a rock layer, not yet seen, above the light-colored bedrock that had eroded away into pebbles.
The tower probably formed when molten rock, pushing upward, encountered a hard rock layer and was forced to spread into a flat-topped shape.
Mr. Laut said that the amount of pressure needed to force bitumen through the protective rock layer "is significantly higher" than that used by the company.
As opposed to a confined aquifer, the water table in an unconfined aquifer system has no overlying impervious rock layer to separate it from the atmosphere.
The type section for the Gelasian Stage, the rock layer laid down during the Gelasian Age, is found at Monte San Nicola near Gela, Sicily.
Gunflint microfossils, assemblage of microscopic fossils uncovered in the Gunflint Iron Formation, a rock layer about two billion years old exposed in western Ontario, Canada.
The plan is for a complex array of 333 deep wells, filtration plants and subterranean bubbles of fresh water created within a deep, porous rock layer that is naturally flooded with brine.
The process is carried out vertically or, more commonly, by drilling horizontally to the rock layer.
