Fig. 12.—Horse (wall engraving) outlined in black, cave of Niaux (Ariège).
Fig. 13.—Horses: A, wall engraving (cave of Hornos de la Péna). B, wall engraving from cavern of Combarelles. C, engraved on reindeer antler (Mas d'Azil). Note the halter in A and in C; also note the heavy head and face of B like that of Prejalvski's horse.
No estimate can be made of the time represented by the 65,000 feet of fossiliferous strata known to us and the same thickness of non-fossiliferous deposit which precedes them. There are no facts known upon which a calculation of the related lapse of time can be based. But most geologists would agree that whilst we have good ground for assigning half a million years to the formation of the Pleistocene strata, it is not an unreasonable supposition that the period required for the formation of the fossiliferous rocks which precede them in time, is not less and probably more than five hundred million years.
Fig. 14.—Drawing (of the actual size of the original) of a flat carving in shoulder-bone of a horse's head, showing twisted rope-bridle and trappings. a appears to represent a flat ornamented band of wood or skin connecting the muzzling rope b with other pieces c and d. This specimen is from the cave of St. Michel d'Arudy, and is of the Reindeer period. This, and others like it are in the same museum of St. Germain.