I found Gen_Mesa in the scenery files. Where is this located in flight sim?
I'm not sure where to find that in the sim, but what I believe you are looking at is a texture for an object (not sure about the 'scenery' you mentioned) in the FSX object library.
You can look around and see all the objects in here.
And if you have FSX Deluxe, you can install the SDK and make scenery with those objects.
Hope this helps
Thats where i found it, in object placement tool.