Harry Hess proposed that the _______. 

A metamorphic rock is similar both in mineralogy and texture to its parent rock.

A(n) _________ is a contact in which an erosional surface on a pluton or metamorphic rock has been covered by sedimentary (or volcanic) rock. 

. _____ can occur when water-saturated soil turns from a solid to a liquid as a result of an earthquake. 

Half life is the time it takes for a given amount of a radioactive isotope to decay to half its original amount

Longshore currents transport most of the beach sand parallel to the shoreline.

Sandstones and gravels make the only aquifers; no other rocks are useful.

The greater part of the sand from most beaches comes from ____. 

Deep rocks behave as _____ material under stress rather than breaking. 

A(n) _________ aquifer is completely filled with water under pressure and is separated from the surface by an aquitard.