Elemental Plane of Earth
The Elemental Plane of Earth is the elemental earth plane of the Prime Elemental Planes. It is the ultimate source of beings such as earth elementals and wyrdlings. Very little seems to be established about it thus far, such as if there is breathable air. Elementals of the earth live under the ground in Elanthia, or exist as rock formations, such as Ghatha the Great Elemental of the DragonSpine Mountains.
The Elemental Confluence
The Elemental Confluence is a composite realm of elemental planes merging, and so is not a pure representation of any given one of the Prime Elemental Planes. However, there are some regions of it that seem almost purely earth based, notwithstanding having other details such as breathable air. The following are some examples of more or less pure elemental earth in the Confluence:
[Elemental Confluence - 23287] A huge earthen monolith rises in the distance, jutting up from the ground to form a jagged cone of rock. From the mountain's edges, huge boulders constantly tumble, slowly forming piles of scattered stones before they are swallowed up by fissures forming periodically along the ground. Obvious paths: southeast [Elemental Confluence - 23329] Vibrations undulate through the ground, the charged pulses tearing up dirt and rock and crushing entire swathes of boulders as it travels outward in all directions. Moments later the ground reforms, healing itself as giant stones claw back up to the surface, only to collapse again beneath each additional wave of crippling energy. Obvious paths: southwest