I know this might be late, but the answers are glaciers, underground, rivers, and streams. Hope that helps:-]
The answer is Dike.
In Geology, Dike is a sheet of rock formed in a fracture in a pre-existing rock body. Magmatic dikes are formed when magma intrudes into a crack then crystallize. It is an igneous body with a very high aspect ratio.
C !! as it can shows the development of the plants over time