La Crânière is a sheer rock face close to the former stopping point of Lahage, in the Chevratte valley. It is also known as Gros Cron after the local name for this particular type of limestone. The rocky hillock is formed of multiple layers of cron (travertine), a greyish spongy rock, laid down over thousands of years by water from a spring rich in calcium carbonate, the substance that creates stalactites. Under Roman rule, a public bath was built around this source. Between the Middle Ages and the French Revolution, the hollow at the foot of the rock housed a hermitage. The site of la Crânière is listed by the Historical Monuments and Sites Commission.