Rocher Blanc (St-Chaffrey)
Access by cable car (summer) from Saint-Chaffrey or Briançon followed by a short half-day walk.
The path is marked but there are somme tricky parts.
This route (starting at the Prorel pass and passing by the White Rock peak) runs through 250 million years of Briançonnais geological history from the Carbonifrous (300 million years) to the Tertiary (40 million years).
The path intersects a succession of sedimentary layers in the "normal" stacking order, that is to say fron the oldest to the most recent.
Warning: the path is marked but there are somme tricky parts.
Representative outcrops are identified by small numbered plates.