The Lower Greensand

The Greensand Ridge is an outcrop of the Lower Greensand. These sands were laid down in a seaway around 100 million years ago, a period known as the Lower Cretaceous. This was an exciting episode in Bedfordshire’s geological history: after 40 million years as dry land, the area was suddenly flooded by the sea. The water burst across what is now southern England, forming a narrow channel running southwest from the Wash, across Bedfordshire, and onward to the Isle of Wight. This was part of a world-wide event caused by global warming, for sea-level continued to rise and flooded much of the Earth!

A view from a Greensand pinnacle over the gravels and clays of the Ivel Valley.

Bedfordshire’s Lower Greensand is unique, because here the estuary of a large river met the Cretaceous sea. The name Woburn Sands marks the difference in the sands and fossils (or lack of fossils) in this area.

There are three different sands in the Woburn Sands: the Red Sands, the Silver Sands (exposed here), and the Brown Sands. A phosphate pebble bed marks the base of the Greensand but in many places the Brown Sands are thin or missing.

For more info try the pdf leaflets (hover over the links for file sizes) The Lower Greensand, the Basics and The Lower Greensand for Geologists.