just Naomi 🏳️⚧️Some say that geology is boring - and some say that geologists bother rocks. All we know is that this geology itself is bored.
It is a lump of London Clay that I picked up on the Essex coast. It was a uniform deep grey then but it has become desiccated. It didn't have those cracks when I picked it up, either. The holes are where it has been bored by piddocks - shellfish rather like clams. In their larval stage, the said piddocks settle on the clay and other soft rocks and burrow as they grow.