The cause of this wide difference of opinion may arise from the failure to observe the fact that the older the formation in which a skull is found, the lower is the type. The ordinary observer, judging by the cast of the skull, would see nothing ape-like about it, and certainly would fail to see any indications of a philosopher. NEANDERTHAL SKULL. The Neanderthal skull was taken from a small cave or grotto in-the valley of the Düssel, near Düsseldorf, situated about seventy miles north-east of the region of the Liége caverns. The grotto is in a deep ravine sixty feet above the river, one hundred feet below the surface of the country, and at a distance of about ten feet from the Düssel River. It is fifteen feet deep from the entrance (_f_), which is seven or eight feet wide. Before the cavern had been injured, it opened upon a narrow plateau lying in front. The floor of the cave was covered four or five feet in thickness with a deposit of mud or loam, and containing some rounded fragments of chert. Two laborers, in removing this deposit, first noticed the skull, placed near the entrance, and further in met with the other bones. As the bones were not regarded as of any importance, at the time of their discovery, only the larger ones have been preserved. [Illustration: FIG. 9. SECTION OF THE NEANDERTHAL CAVE. _a._ Cavern sixty feet above the Düssel, and one hundred feet below the surface of the country at _c_. _b._ Loam covering the floor of the cave near the bottom of which the human skeleton was found. _c_, _a_. Rent connecting the cave with the upper surface of the country. _d._ Superficial sandy loam. _e._ Devonian limestone. _f._ Terrace, or ledge of rock.]