A comment on ‘a note on the characteristics and possible origins of desert varnishes from Southeast Morocco’ by Drs. Smith and Whalley

This note queries the discussion of the origins of ‘desert varnishes’ (Smith and Whalley, 1988), with particular reference to manganese‐rich conditions. The case for a biotic model of varnish development is proposed and illustrated as opposed to the abiotic model put forward by Smith and Whalley.