Great picture, thanks for posting. Obviously, a sedimentary formation they are standing on. Do you know the name & age of the formation?
It’s at the beginning of the text.
I have never been to that area in the Alps and don’t know the name of the formation. The closest I have been is to the NW in Chamonix, France and the Mount Blanc part of the Alps which seemed to be pretty solid granite. Farther NW in Switzerland the Matterhorn and Eiger are very slaby shale though.