in consequence of a cave-in. The vestibule leads to a very large hall divided into two chambers by a mass of fallen rock. The chamber to the left is 40 by 10 meters. The one on the right leads to the series of halls and corridors. At the close of the Quaternary a cave-in at the entrance had effectually sealed the cavern. The fauna is that of the cave bear.
The paintings and engravings are found in all parts of the cavern, especially in the first chamber to the left after entering. The beauty, size, and degree of preservation of these works of art are admirable. Some of the engravings are deeply cut; others are gently incised by the aid of a sharp point. The greater part of these decorations, however, were executed in color, either black or red or both. The most remarkable are those in polychrome of the left chamber near the entrance. While some of the decorations represent animal figures, others are incomprehensible signs and symbols. They do not all date from the same epoch. The deeply-cut figures of the left chamber recall those of Chabot, Pair-non-Pair, and La Grèze. Mural art at Altamira admits of grouping under four categories: (1) Deeply incised engravings and line drawings (dessins au trait) in black; (2) black or red figures; (3) fine engravings, and (4) polychrome frescoes.
Line-drawings and figures in black are abundant along the corridors. The ceiling of the left chamber has many traces of black line-drawings (pl. 5, fig. a) generally in bad state of preservation. Some of the figures in black are shaded in (modelés) , and in this respect are quite equal to the polychrome figures.
The second layer of paintings includes the black or red frescoes which are seldom combined in the same figure with engravings.
Fine engravings are numerous and often made over the black line-drawings, that is to say, were more recently executed.
The polychrome frescoes are remarkable for vigor, exactitude and the command of colors—red, brown, black, and yellow—which mix and grade into numerous tints. A group of twenty-five of these is seen on the ceiling of the left chamber. Some are older than others. In the later figures, black contours and engravings combined play an important rôle. The surface to be included in the field of the projected figure was washed and scraped. A black line was traced fixing the contours. The necessary colors were then added. In many cases, one sees divers touches of the brush, each marking a tuft of the mane or the dewlap (pl. 5, fig. b), while the large colored surfaces were covered with a thinner mixture of color, graduated by washing or gouache. This work accomplished, the artist often retouched the figure, washing or scraping, removing the color in places to secure the lighter effects or to detach the limbs folded on the body. Spots for decoration were often chosen that give, without much extra effort, the effect of a colored bas relief. The frescoes
