Wall Bowls, Pools, Foundations
There are different bowls here: wall bowls, shells, and fountain bowls.
Wall fountains bowls mount to a sturdy wall and will specifically say "Wall" in the name. Other fountain bowls and basins such as the "shell" bowls are intended to be placed on a pedestal, not mounted to a wall.
Shells are intended to be placed on a pedestal or other support. The water feature such as a statue will be placed on the small platform at the edge of the shell.