After leaving the Bark in the Park area, I walked across the parklands and through the olive grove towards home.
On a bare patch of ground I saw something that surprised me.
In one of them eroded earth was exposing shells usually found on a beach.
Here's a closer look->
Perhaps left behind by long ago picnickers?
Scooped up with earth and used as landfill for the area?
It's right on the southern edge of the olive groves.