Stone Pillar

The Stone Pillar is the second unlockable pillar. A pillar is a stackable form of a foundation, which is required for building any kind of housing or storage structure. You can stack up to 9 pillars in ARK: Survival Evolved Mobile.

Construction
The Stone Pillar can be placed on even or slightly uneven ground, or on the top or bottom of foundations, ceilings, or other pillars. Once the first Pillar is placed, subsequent pillars can snap into place on the top or bottom of the first one, provided there is adequate room to do so.

A pillar or series of pillars with the bottom touching the ground and a ceiling on top will function as a foundation, providing support and allowing structures to be built on top of it.