The flooded brickpits at Yaxley, beside Hampton Vale, preserve a glimpse of the Middle Jurassic sea beneath modern Peterborough. Weathering of the fossil-rich Oxford Clay has yielded oysters, belemnites, ammonites and occasional marine-reptile remains along the lake embankment. The exposed shore changes with water level and vegetation, and access to lakeside paths does not automatically permit collecting on the banks. Check current signs and obtain permission before leaving the paths or removing material. Jurassic, Lake Embankment, Rating: ♦♦♦♦♦