There is a Legacy version here.


Source Player Core pg. 455
Effects with the earth trait either manipulate or conjure earth. Those that manipulate earth have no effect in an area without earth. Creatures with this trait consist primarily of earth or have a connection to magical earth.

These planes are mostly solid. Travelers arriving upon an earth plane risk suffocation if they don’t reach a cavern or some other air pocket within the plane’s solid matter. Creatures who can’t burrow are entombed in the plane’s substance and must attempt to dig their way toward an air pocket. Air creatures are ill at ease, as they rarely have the space to move freely through even the loftiest warrens.