Gold found by source of river (6)
I believe the answer is:
orwell
'river' is the definition.
(I've seen this before)
'gold found by source' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'found by' means one lot of letters go next to another.
'source' becomes 'well' (well is a kind of source).
'or'+'well'='ORWELL'
'of' is the link.
(Other definitions for orwell that I've seen before include "George --, novelist" , "George . . . . . ., writer concerned with social justice" , "George _______, nom de plume of Eric Blair" , "banker" , "The Road to Wigan Pier author" .)