Le Creux-de-Souci, Puy de Dome. (Martel, _Les Abimes_, 1894, Page 387.)--This is situated 5 kilometers southeast of Besse-en-Chandesse. It is a large lava cavern with the entrance directly in the middle of the roof. The bottom is partly filled by a lake. The depth from the surface of the ground to the lake is 33 meters; from the smallest part of the opening to the lake the depth is 21.50 meters. Down this last portion one can descend only by means of a rope ladder. The temperature is extremely low; in general near freezing point. In June, July, August and November 1892, Monsieur Berthoule, _maire_ of Besse, did not find any snow. On the 10th of August, 1893, on the contrary, he found at the bottom a heap of snow, which he thinks was formed in the cave itself, by the freezing during their descent of the drops of water which are constantly dripping from the roof. He reports landing on _une montagne de neige, de neige blanche_. On several visits, Mons. Berthoule noticed carbonic acid gas in dangerous quantities. There was none at the time he observed the snow heap, but ten days later he found it impossible to descend into the cave as the carbonic acid gas came up in puffs to the entrance. In the lake, Mons. Berthoule discovered a variety of Rotifer, _Notholca longispina_, and also several algæ and diatoms. The _Asterionella formosa_ is the most remarkable from its abundance: it exists in some of the lakes of the Alps, but not in those of the Pyrenees. Aven de Lou Cervi, Vaucluse. (Martel, _Les Abimes_, page 563.)--This is a cold cave. It belongs to the class which Mons. Martel calls _avens à rétrécissement_, or _abimes à double orifice_. In September, 1892, Mons. Martel noted a temperature of 6.5° at 53 meters; of 6.8° at 64 meters. Mean temperature of locality, 8.75°. Igue de Biau, Lot. (Martel, _Les Abimes_, page 304.)--Cold cave. Temperature on 13th July, 1891: 5°. Fosse Mobile, Charente. (Martel, _Les Abimes_, page 380.)--Cold cave. Temperature on 11th April, 1893: 7°. Aven de Deidou, Causse Méjean. (Martel, _Les Abimes_, page 223.)--Cold cave. Temperatures on 14th October, 1892: outside air, 4°; at bottom, 6.5°. Aven des Oules, Causse Méjean. (Martel, _Les Abimes_, page 227.)--Cold cave. Temperatures on 21st October, 1892: outside air, 2.5°; at bottom, 4°. Windhole Cold Caves near Roquefort, Aveyron.--They lie 13 kilometers from Millau, at an altitude of about 600 meters, and are utilized in the manufacture of Roquefort cheese. Aven de Carlet, near la Roche Giron, Basses Alpes. (Martel, _Les Abimes_, page 53.)--Lumps of ice are reported to have been taken from it.