Avert filly travelling in depressed area in Africa (4,6)

I believe the answer is:

rift valley

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'in depressed area in africa' is the definition.
I can't tell whether this defines the answer.

'avert filly travelling' is the wordplay.
'travelling' indicates an anagram.
'avert'+'filly'='avertfilly'
'avertfilly' anagrammed gives 'RIFT VALLEY'.

Can you help me to learn more?

(Another definition for rift valley that I've seen is " Geographical feature".)

I've seen this clue in The Telegraph.

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