In the south of Courtelary, on the chain of the Chasseral, with 1320 meters of altitude, a pit is in which the ice persists all the year. It is the Hollow-of-ice .

During the winter, snow fills up this hole from 30 to 40 meters of depth, there accumulates, packs, and forms in the interior part a Névé which is transformed into Glacier. While coming from Cortébert, one reaches the Hollow-of-ice by the firm of the Small Customs . Pretty strolls makes it possible to go to this pit which hides behind Sapin S and Hêtre S.

One can go down at the bottom from the hole by a slipping path, while helping oneself in particular of an iron chain. The hole, from 25 to 30 meters in diameter in its upper part, 15 to 20 meters at the bottom, reached a depth close to 40 meters. This Emposieu (or doline) is a ic phenomenon Karst grounds Calcaire S. water infiltrates, digs the rock, uses it, and carries it inside the geological layers. Water spawning time then a way and this underground river forms with the time of the Grotte S and the vacuums in the ground which subsides sometimes.

As of the 16th century, it Hollow-of-ice was exploited by the anabaptists which extracted some from the Minerai of Fer (Oolithe ferruginous). This iron mine, profitable at the time, made it possible to the peasant-minors to pay their taxes with the prince-bishop. Then, until half of the 20th century, the pit was used by the Métayer S of the area which stored butter, cheese and meat there.