Grotte Roche, a case of
Friday, 29 August 2014

Better get some cream for that.

Despite sounding more like the name for an unfortunate itchy condition than a cave, this was a nice fun trip with Paul, who lives locally in the Vercors. It is situated in the Bourne Gorge, and was a nice relaxing trip after the epic-ness of our Berger de-rig (whereupon exiting we had both declared our intention to “never cave again) It involves a nice mix of varied passage types and a short through trip can be undertaken from the top entrance. The main breakthrough in the cave was achieved after the Vercors guide book was printed so there is not much info about it, though Paul knows it well.
The top entrance is situated approx. 50 ‘ 100m above the road in the gorge, accessible via a steep incline up a limestone ledge overgrown with trees. The start of the path up from the road is strangely marked by a via-ferrata cable (strange as it is along the side of an easy wide path with pretty much no chance of falling), and heads up pretty much opposite the huge bottom entrance (which is not visible when standing on the road). The top entrance is found in the base of the cliff on the back side of the ledge, and is an obvious low passage. It leads through a short draughty crawl which pops out into large fossil passage. Interestingly this must have been entered years prior to cavers discovering it, as the passage is intersected by a large water tube from the hydro-electric plant nearby, which is pretty old. The pipe has sprung a leak meaning the once fossil passage now has a small stream in it.

The small stream is followed down a series of climbs and a couple of pull-through pitches and lands in a large junction. Here we headed away from the entrance, through a few small bits into very large fossil passage ‘ a continuation of the development obvious at the bottom entrance (this appears to pre-date the formation of the Bourne Gorge as another fossil passage of similar dimensions can be seen on the opposite side of the gorge). We stopped for photos at a couple of sections of pretties, Holly taking, with Paul giving plenty of suggestions on how to take them and me doing my best to pose (no gurning in any photos!!).

The large passage closed down at a section of pretties, but following a ladder up into an obscure crawl led through phreatic tubes into a further continuation of the large phreas (which apparently is heading steadily up the gorge). Interestingly a stream enters and flows “upstream against the direction of phreatic development, down muddy inclining passage. This would have formed with the water flow heading up the slope (and hence down the gorge ‘ as would be expected) as the passage would have been totally flooded and the water pushed up-slope under a head of pressure.
The passage ends miserably with the water flowing into an inaccessible low duck / sump now full of sediment. Who knows what passage lies beyond this currently impassable barrier, as the large phreatic passage obviously came from further up the gorge (it can be seen again in other large caves further up-stream).
Paul led us on a circular route on the way out through a series of tight rifts and beddings ‘ Mendip style. The main passage exits dramatically in the side of the gorge ‘ an impressive spot. We then headed back to Pauls for tea consisting of Berger left-overs and had a fun evening of expedition gossip

This is a fun little trip as an easy option in the area