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Rh as representing 2,000 years, the time required for the whole series of deposits is estimated at 24,000 years. The total time elapsed since the maximum advance of the Würm glaciation is still longer, 30,000 years being none too high an estimate for it.

When could Wildkirchli have been inhabited? It lies within the region of glaciation. It could not have been occupied during the Würm glacial period, because it is at a height of 1,500 meters, while the snow line of the Würm glaciation was only 1,200 meters. It is self-evident that man could not have taken up his abode above the snow line. Even during the Bühl stage of the glacial retreat the snow line was still as low as 1,500 meters. Man could have come there only after the Bühl stage. But after the Bühl stage we have a different fauna and flora; so that man must have inhabited Wildkirchli before the last (Würm) glacial epoch, that is to say during an interglacial (Riss-Würm) epoch with climatic conditions similar to those of the present day.

During the last glacial epoch the Wildkirchli caverns were filled with ice or snow, and hence no deposits of any kind were formed. The sterile layer one-half meter thick at the top of the floor deposits represents the accumulation since the close of the glacial period. If we allow 30,000 years for post-Würmian times we must allow as much more for the last glacial epoch. Thus to reach the Riss-Würm interglacial period and man's occupancy of Wildkirchli caverns would mean going back about 100,000 years. We have here an atypic late Mousterian, or perhaps lower Aurignacian, industry.

An interesting feature in the development of our knowledge of cavern life is that pertaining to paleolithic mural decorations. These were first discovered in the cavern of Altamira, province of Santander, Spain, explored in 1879 by Sautuola. They were, however, not accepted as authentic. About ten years later Léopold Chiron reported mural decorations in the cavern of Chabot (Gard), but the discovery was received with the same skepticism as that which befell the earlier announcement of Sautuola. With the discovery by Émile Rivière, in 1895, of wall engravings in the cavern of La Mouthe (Dordogne), the tide was finally turned in favor of their authenticity. Thereupon other caverns were searched and revealed similar phenomena. In 1906 Francois Daleau announced the discovery of wall engravings at Pair-non-Pair (Gironde), and the following year Félix Regnault found frescoes on the cavern walls of Marsoulas (Haute-Garonne). Since 1900 discoveries of this class are to be numbered by the dozen, and the literature has been enriched by more detailed accounts of the cavern decorations discovered prior to the date in question.

The cavern of Altamira, situated near Santillana, is a series of grand halls united by corridors. The entry is modern, being formed