CURRENT geological investigations into the ancient rocks of Leicestershire have revealed three occurrences of the clay mineral palygorskite. These are in the lower quarry at Bardon Hill, the Cliffe Hill quarry and the Warren quarry at Enderby. At all three localities the palygorskite is present in joints in dioritic rocks. In every case its identification has been checked by X-ray powder techniques. No sepiolite lines were detected on any of the powder photographs.