a low area or hole in the ground that is formed especially when soil and rocks are
removed by flowing water. Source: Merriam-Webster's Learner's
A natural depression in a land surface communicating with a subterranean passage, generally occurring in limestone regions and formed by solution or by ...
Jan 21, 2011
Mar 6, 2013
a depression in the ground communicating with a subterranean passage ( especially in limestone) and formed by solution or by collapse of a cavern roof.
cesspool; ⌂ a saucer-shaped surface depression produced when underlying material, such as limestone or salt, dissolves or when caves, mines, etc. collapse.
a cavity in the ground, especially in a limestone formati...
Mar 4, 2013