Reference the end of many prehistoric animals? (9)

I believe the answer is:

thesaurus

'reference' is the definition.
(I know that thesaurus is a type of wordbook)

'the end of many prehistoric animals?' is the wordplay.
'end of many prehistoric animals?' becomes 'saurus' (suffix in dinosaur names).
'the'+'saurus'='THESAURUS'

(Other definitions for thesaurus that I've seen before include "Volume of synonyms" , "Wordy gathering" , "Word book" , "Reference work" , "work we may refer to" .)

I've seen this clue in The Times.

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