It has been remarked that, although these paintings belong to what is called the "reindeer epoch," yet in the cave of Altamira there are no representations of reindeer, but chiefly of bison and wild boar. It is also remarkable that in the case of the painted rock shelters of Calapata (Lower Aragon) and of Cogul (near Lerida, in Catalonia), no reindeer are represented; but on the former there are very admirable drawings of the red deer, and on the latter silhouettes of the bull, of the red deer, and the ibex. In fact, no representations of reindeer have been observed on cave walls or rock-shelters south of the Pyrenees. It is possible that this may be due to the date of the Spanish paintings being a good deal later than that of those French cave-paintings which show reindeer, mammoth, and rhinoceros. And we have to bear in mind that in the North of Africa (Oran) engraved drawings on exposed rocks are known, which are for good reasons attributed to the Neolithic period; that is to say, they are later than the Reindeer epoch of the Palaeolithic period, whilst some are even much later. In any case we have to remember that there are two very different and possible explanations of the presence or absence either of certain animals' bones or of representations of certain animals in one "decorated" cave and not in another. The one explanation is that animals have succeeded one another in time in Western Europe--changing as the climatic conditions have changed--and that when, in two cave-decorations or cave-deposits compared, the animals are different, the cause may be that the one deposit or cave-decoration is more recent than the other. The other explanation is that (as we well know) at one and the same moment very different animals occupy tracts of land which are only a hundred miles or so apart, but differ in climate and general conditions. At this moment there are wild bears and also wolves in France, but none in England; the elk occurs in Sweden and Russia, but not in the West of Europe; the porcupine in Italy and in Spain, but not in France. As late as the historic period the African elephant flourished on the African shore of the Mediterranean, but not in Spain; now it is not found north of the Sahara at all. So we have various possibilities to consider in comparing the animal pictures on the cave walls of Spain with those found in France, and may well suspend judgment till we have knowledge of a greatly extended area. * * * * *