Resting on (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
atop
'resting on' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for atop that I've seen before include "At the summit of" , "on the head" , "In superior position" , "highly placed" , "Upon" .)