THE ambitious project for a regional survey atlas covering some 200 square miles around the Borough of Croydon was begun by the Croydon Natural History and Scientific Society so long ago as 1913. Despite the difficulties of war-time conditions, it has been continued by the issue this year of a third series of maps and printed matter (Proc. Croydon and Dist. Nat. Hist, and Sci. Soc.). In contrast to similar local surveys which have been attempted in other parts of Great Britain, the Croydon scheme is based essentially on the idea that a regional survey is never of necessity complete, and hence the actual work is to be contained in a loose-leaf binder which was issued with the first series of maps ; the contents as originally planned can therefore be added to as experience and the progress of knowledge may dictate.