Need help to complete last four. Some letters may be wrong so please point out my errors.
50a Like some spirits? Once maid got drunk (8) I thought it was anagram of once maid but can't fit in with letters I have. D?E???I?
46d Fern starts to wilt on our dry savannah in Africa (7) W?????A
54a gradual assimilation of universe is not requiring carbon (7) O?M?S?? Could this be OSMOSIS and if so why.
47d like limestone with aluminium in small volume with core of mica (6). ?A?C?C
Thanks in anticipation for any help