Grey crustose thallus growing on limestone. Large hemispherical perithecia each with crater in the top giving flat-topped profiles. Possibly Acrocordia salweyi.
Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
Thanks for help with the identification.
Lat/Lng: 54.0865, -2.258
OS grid ref: SD832656