Very important, indeed, is the age of the sculpture and bas-reliefs found in Laussel. The human sculptures are determined to be of late Aurignacian age, because they are buried in an early Solutrean talus. The splendid wall sculptures of the series of horses in the Cap-Blanc shelter, near the Laussel shelter, are shown to be of middle Magdalenian age, because of the upper Magdalenian strata which covered and partly concealed them. [Illustration: FIG. 156. Primitive painted outlines of animals from the cavern walls of _Font-de-Gaume_, Dordogne, attributed by Breuil to the early Aurignacian. The outlines represent the horse, ibex, cave-bear, wild cattle, and reindeer. After Breuil.] In other instances we can date a drawing in a cavern by the period at which the opening was closed; for example, the cave of La Mouthe, Dordogne, was closed in by a Magdalenian layer of flints which touched the roof and firmly sealed up the entrance until recent times. Again, at Gargas, Hautes-Pyrénées, we know that the last occupation by the Crô-Magnons was near the end of Aurignacian times, as indicated by a hearth filled with late Aurignacian flints and with the remains of the bear, hyæna, horse, and reindeer; the opening of the grotto was buried beneath these foyers, which obstructed the entrance until the cave was rediscovered at a comparatively recent date. Also at Marsoulas, Haute-Garonne, there are two hearths, one late Aurignacian, the other late Magdalenian; the grotto was then closed until recent times. The grotto of Niaux, on the Ariège, which contains fine examples of drawings of middle Magdalenian times at a distance of 1,800 feet from the entrance, was protected for a long period by a lake 6 feet deep and several hundred feet long. At Altamira, near Santander, the superb frescoed ceiling was buried, long before Neolithic times, by the closing up of the entrance, which was rediscovered only about thirty years ago. [Illustration: FIG. 157. The woolly rhinoceros, painted in red ochre with shading and partial representation of the hair, in the cavern of _Font-de-Gaume_, Dordogne. Attributed by Breuil to the late Aurignacian. Possibly Magdalenian. After Breuil.]