Interesting article bout concretions that mentions fossils.

Concretions in sandstones of the Inner Hebrides, Scotland
Mark Wilkinson, June 2016, Deposit Magazine
[depositsmag.com]

The Great Estuarine Group (Jurassic, Scotland)
The Palaeontology Newsletter, 1992
[www.palass.org]

Yours,

Paul H.

"The past is never dead. It's not even past."
William Faulkner, Act 1, Scene III, Requiem for a Nun (1951)