Jurassic Limestone Ridge

The Jurassic Limestone Ridge is a west-east aligned feature located between the Nene Valley and the Welland Valley. It is an area of complex Middle Jurassic bedrock underlain by mudstones (clays), sandstones and principally limestones, including the Lower Lincolnshire Limestone & the Cornbrash. In places there are patches of Oadby Glacial Till, Glacio-fluvial Gravels and Head.

The dissected ridge reaches above 70m OD. There are poorly drained soils developed on till and mudstones, and well-drained soils on gravels and limestone. There is also a small area of similar Jurassic bedrock geology to the south of the Nene valley forming the Sibson Ridge.

There are no geological SSSI and three LGS: Swaddywell Pit/Helpston Prick Pit, Thornhaugh Quarry and Cross Leys Quarry

Barnack Hills and Holes NNR preserves the site of an important Medieval limestone quarry, famous for the building stones that were used for Peterborough and Ely Cathedrals as well as many other buildings such as Ramsey Abbey. Castor Hanglands and Bedford Purlieus are also both NNRs.