Beside these contrivances there were also lateral recesses in which the defenders might lurk in ambush, to rush forth to hew at the enemy, or at least to extinguish his torch. Almost invariably these hypogees have two exits or entrances, so that those within could escape by one should the enemy force the other, or endeavour to smoke them out. Moreover, to keep up a circulation of air, and to obviate the contingency of being smoked out, these underground retreats are almost invariably supplied with ventilating shafts. The marks made by the implements employed in hewing the rock are always distinctly recognisable. Moreover within, sunk in the floor, are silos for the storage of grain, the soil often somewhat higher about their orifices than elsewhere, and sometimes provided with covers. Niches for lamps may be seen, also cupboards for provisions, in which have been found collections of acorns, walnuts, hazel-nuts and chestnuts carbonized by age. [Illustration: Sections. Château of Fayrolle (Dordogne). A. Entrance. B. Continuation, unexplored. C. Shaft. DD. Doorways. E. Modern entrance. FF. Store chambers. G. Large chamber. H. Slot for stabbing assailants. K. Ventilating shaft.] A typical _souterrain réfuge_ is that of the Château de Fayrolle, not far from Riberac on the Dordogne. It was accidentally discovered when the proprietor was levelling for terraces and gardens. A glance at the plan will save a description. A refuge at S. Gauderic has been explored. The region is one of lacustrine deposits called the Sandstone of Carcassonne; it is friable, argilaceous marl. The opening into the hypogee is in the middle of a field, and there are no indications around of the deposition of the material extracted in the formation of the retreat, so as to betray its presence. The visitor descends by a dozen steps into a long corridor, sinuous, and inclining downwards, about 1 foot 8 inches wide, and 4 feet 6 inches high. The passage exhibits rebates in several places, into which door-frames had been fitted, as well as square holes into which the beams were run that fastened the doors. It leads past several side-chambers into which the defenders might retire, so as to burst forth suddenly and unexpectedly on the foe, smite him and extinguish any torch he bore. The corridor leads to a rectangular hall 22 feet long and 7 feet high, vaulted and ventilated by three circular airholes, 6 inches in diameter. There are numerous silos in the floor, and fragments of coarse grey pottery turned on the wheel have been found there. [Footnote: _Révue de l'Art Chretienne_, Paris, 1868, p. 498 _et seq_.]