The 161c entrance was originally explored by the French Groupe Spéléologique de Clerval - Baume les Dames under the name VSS2 in 1988 and 1989, reaching -285m. They abandoned exploration as it was apparent that it was going to connect into 161, though in fact, that connection at depth wasn't made until 1995 and entailed the discovery of a large amount of very impressive passage ! CUCC's explorations pushed deeper and led to the huge sub-horizontal series off Triassic Park. Since easier ways into those passages were found further down the mountainside, this entrance has not been used.
Photo © Earl Merson, 1999