What is the rock I found on the Delaware river yesterday? I spotted this large striped rock found on Delaware River. Note the fossil in the first picture. What kind of rock is this?
The boulder appears to be dark grey  fossiliferous limestone or dolostone with softer tan layers which might be: limestone or calcareous claystone/siltstone/sandstone.
From the photo, the tan layers do not appear to be shale.

I have a hand specimen which is very similar from southern New Jersey.
It is harder grey limestone inter-layered with light tan calcareous siltstone.