Good composer in The Stones? (6)
I believe the answer is:
gravel
'the stones?' is the definition.
(I've seen this before)
'good composer' is the wordplay.
'good' becomes 'g' (abbreviation).
'composer' becomes 'ravel' (Maurice Ravel).
'g'+'ravel'='GRAVEL'
'in' is the link.
(Other definitions for gravel that I've seen before include "Grit" , "Small stones for surfacing driveways" , "Small stones on paths" , "Rock fragments and pebbles" , "Mixture of small stones" .)