Folded Shelf

This gave me the clue to what I think is the solution to the puzzle. It looks as if some layers of the wall split off and buckled outward and further broke creating a shelf-bracket type geometry. Other strata broke off and landed fortuitously making a larger landing shelf and so on. It would be interesting to hear other peoples theories, but at the time of my writing this post I haven't written the commenting module for the site yet. (but I think I have the schema worked out)

Strata
Puzzle
Canada
Geology
Rockies
Slate