Here are more photos of Concretions that you asked for.
They take various shapes, and probably have various names,
but are, nevertheless, fascinating!
Here's another post I did on concretions with a few more photos.
I called these 'Boobie Rocks' before I found out what they really were!
Here's an interesting link, if you want to know more: https://ww2.kqed.org/quest/2012/01/12/confounding-concretions/
Our World Tuesday