Mounds and banks (Thirlwall) - Source of Reference
The information on this website is based on a range of published and unpublished works. Below is a list of the source of information used in writing this record.
1) This record includes National Record of the Historic Environment Information provided by Historic England on 4 January 2021 licensed under the Open Government Licence [http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/]
1a) Light detection and ranging (lidar) airborne survey, LIDAR Environment Agency LAST RETURN 21-APR-2010