Photo from Le Miroir Des Sports, 05 Feb 1929
Here we see Camille Foucaux exiting the Trou-du-Diable in the 1929 Critérium International. He went on the beat Charles Pélissier that year, covering the 20 km course in 50 m 11 s, besting the old race record by nearly 6 minutes. Foucaux was known for descending into the Trou on the bike, riding out of it was a different matter altogether...
Photo from Le Miroir Des Sports, 08 Mar 1923.
Another, wider-angle view of the rocks - "des rochers de Saint-Germain" - shown in the 29 Jan photo. It's really only the rudest approximation of a course, seemingly only cut recently into the shrubbery, and rather free-form through the large rocks in the upper part of this section. Just looking at the scale of this photo - we're probably talking around 50 feet of descending - gives me goosebumps.
Photo from Le Miroir Des Sports, 14 Dec 1923.
More clambering up rough inclines. These guys are attempting to chase down Roger Lacolle, two-time French champion (1922-23), who would win this race. Not incredibly steep, but certainly steep enough that several riders are putting their hands down to brace themselves! Again we see the bushwhacking element coming into play - this slope has hardly been cleared of its natural brush.
Photo from Le Miroir Des Sports, 13 Jan 1931.
Led here by Hilaire Bertellin, world champion in 1930 (and eventual winner of this race), the peloton approaches the climb of Piscop through the snow, riding along a sunken cart-track. Nothing super-technical here, just a nice shot.