Clearing the coralline crag

Rockhall Wood SSSI at Sutton is a very special place. Designated for its Coralline Crag stratigraphy and relationship with the Red Crag surrounding it, this Crag 'island' forms a low hill above the surrounding fields. The exposures around the sides of the hill tell the story of changing Pliocene sea levels and faunal migrations and extinctions 2.54.5 million years ago. The unconsolidated lithology of the Crags means that these exposures need constant attention and GeoSuffolk was thrilled with the turnout at the Suffolk Coast and Heaths AONB Volunteers Day on March 3rd. Boosted by Environment Agency volunteers we numbered thirteen altogether and luck was with us –the sun shone on this beautiful early spring day. In the morning, two Coralline Crag faces – one with excellent stratigraphy and the other showing the junction with the Red Crag - were refreshed on the east side of the hill. After a picnic lunch, during which a box of chocolate brownies was passed round, we worked on the Coralline Crag/Red Crag unconformity on the south side of the hill. As well as revealing the honey-coloured Crag exposures, we found some of the fossils for which they are renowned: a very large and complete Neptunea contraria; a Scaphella; a Coralline Crag bi-valve cast with adhering Red Crag barnacles; a fossil crab derived from the London Clay. This SSSI is on private land but, if you would like to visit, GeoSuffolk is joining in with Sutton Village Gardens Open Day on June 26th to show its 'Pliocene Forest' on the SSSI site to the public. As well as molluscs the Coralline Crag contains fossil pollen and our 'forest' has living representatives of genera identified by this pollen.

Working on the Coralline Crag/Red Crag junction on the south side of the Crag ‘island’ at Sutton

Biodiversity News— Spring issue

Issue 72 of Biodiversity News is now available to download. To view this edition please click here > Contents include: Polli-Nation project, Great British Beach Clean results, Water Voles thriving in Fenland Drains, The Hive comes to Kew Gardens. To view previous editions (from 2007 onwards) please click here >