Mountain Path(Area)

Name: Mountain Path
Location: Unova Region
Area type: Cave
Pokemon found:
Whirlipede 23 - 25(Common)
Sandile 10 - 20(Common)
Yamask 20 - 23(Common)
Zorua 23 - 27(Rare)
Dusion 32 - 34(Rare)
Amoongus 39 - 42(Very rare)
Liepard 30 - 40(Very rare)
Seismitoad 43 - 56(Horribly rare)
Landscape: Outside the entrance,there is trees surrounding it.There is a broken fence with an item ball that contains a Hyper potion.Inside it's a normal cave with a few movable rocks.It leads to an underground cave that leads back to Sinnoh.
Looks: A huge mountain with an opening at the base.nothing unusual.
Notable places: Underground cave.
History:
It was just recently discovered.Pokemon moved into it first.Many say that in the dawn of time,An aerodactyl flew to the top all the way from Kanto.A scientist dug out a trail to go back to Sinnoh.

I think it would help if you could tell what canon area(s) is this area close to.