yes the hole was there its more like a large drainage ditch in the woods not sewage but a huge drain ditch with leaves and trees in in that just holds water in the rain
Welcome to TNet..........
From the pics it appears to be a type of mica schist........does it flake off when rubbed?
The rock forum would be the place to show that off.
If the flakes are black it is a biotite schist, if clear/translucent it is a muscovite schist..........google both and see if the results match your specimen.