caving_fox said:Is that on a ridge? Water lapping in on both sides, but not quite overflowing?
Pitlamp said:They look like something I've seen in Peak Cavern's Far Sump Extension.
If so, are they formed by unidirectional flow eroding the mud deposit? Clay particles get stuck to each other by molecular forces and don't then separate easily. It can lead to unusually shaped residues when they're partially eroded by moving water, when some parts of the sediment are better bonded than others.