Before the war suspended such enterprises, the savants of France were exploring the wonderful sub-fossil remains of Algeria which revealed to us the existence there of a mammalian fauna resembling that of modern tropical Africa, of the region south of the Sahara. With that fauna were mingled in a very interesting degree creatures which at the present time are restricted to India. For instance, there was something so like an Indian elephant that it might be called the Indian elephant, existing almost down to the human period in Algeria. There was a wild camel, an equine resembling a zebra; there were gnus, hartebeests, oryxes, and other types of modern African antelopes; and there was a Tragelaph allied to the Nilghai; there was a huge buffalo with almost incredible horns—14 feet long—incredible were it not that its existence is proved not only by its fossil remains but by the drawings of primitive man. The Foureau-Lamy Expedition, I believe, found many of the dry torrent-beds of the elevated Ahaggar region choked with hippopotamus bones. There is everything to point to quite a recent and rapid change in the climate of the Sahara, which, well within the human period, was a region abounding in water derived from a heavy rainfall, and richly endowed with forest areas, as we may see from the remains of petrified trees. This will bring home to you what gains might come to science and to our knowledge of the evolution of life on this planet if we could only thoroughly explore the Sahara, and above all such regions as the Tibesti highlands.