Start wandering around area to find geological features (6)

I believe the answer is:
strata
'geological features' is the definition.
Although both the answer and definition are plural nouns, I don't understand how one could define the other.
'start wandering around area' is the wordplay.
'wandering around' indicates anagramming the letters (I've seen this in other clues).
'area' becomes 'a' (maths abbreviation).
'start' anagrammed gives 'strat'.
'strat'+'a'='STRATA'
'to find' is the link.
Can you help me to learn more?
(Other definitions for strata that I've seen before include "Beds of sedimentary rock" , "Levels, grades or social classes" , "Parallel layers" , "Layers of rock on earth's surface" , "Layers as of rocks in earth's crust" .)
