Rocks

I wanted to paint rocks and mountains. I did not have a good reference for a cave mouth and this is how I thought it should look. I thought it should look like a shadowy whole and when my mom got the first look at it asked me if this was another kind of rock too (maybe a granite boulder)? I told her it was a partial view of a cave... obviously it is not perfect since mom. did not recognize it on the spot.
Anyway I hope you like it and feel free to comment.

References:
marinaawin.deviantart.com/art/…
marinaawin.deviantart.com/art/…
marinaawin.deviantart.com/art/…
marinaawin.deviantart.com/art/…
marinaawin.deviantart.com/art/…

Soft pastels on paper.