Putting my two cents in here! An alternate explanation for the fingers having valleys and all that fun stuff could just be down to the geology. The valley could stay if we accept that there is folding of rock layers in the fingers.
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The fingers themselves could be anticlines, and the valleys between synclines. The softer layers of rock on the surface would get washed down into the synclines leaving behind the linear shape of the fingers.
That being said, it’s the sort of thing that wouldn’t be immediately obvious to the passerby and unless you knew about this stuff you would be confused by it. This may all just be moot. Who knows, but do with this information what you will!
App is looking lovely