Bunch of notes one found in gully (4)
I believe the answer is:
wadi
'gully' is the definition.
(I know that wadi is a type of gully)
'bunch of notes one' is the wordplay.
'bunch of notes' becomes 'wad' (wad of banknotes).
'one' becomes 'i' (Roman numeral).
'wad'+'i'='WADI'
'found in' is the link.
(Other definitions for wadi that I've seen before include "Seasonal water channel" , "Seasonally wet ravine" , "Mainly dry ravine" , "Seasonal water course (in Arabic-speaking lands)" , "(Usually) dry desert riverbed" .)