Quantities going to the ends of the earth! (4)
I believe the answer is:
tons
'quantities' is the definition.
(ton is a kind of quantity)
'to the ends of the earth' is the wordplay.
'the ends of' says to hollow out the word (remove centre letters).
'the earth' becomes 'ness' (ness is a kind of earth).
'ness' with its middle taken out is 'ns'.
'to'+'ns'='TONS'
'going' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for tons that I've seen before include "Lots" , "Each is equivalent to 2240 pounds" , "Loads (sl.)" , "A lot" .)