Geological Society. 119 



lower symphysial border is not thickened and rounded, as in man, 

 but produced iuto a thin inwardly-curved flange, as in the apes. 

 The ascending ramus is comparatively wide, with extensive in- 

 sertions for the temporal and masseter muscles, and a very slight 

 sigmoid notch above. Molars 1 and 2, which occur in their 

 sockets, are typically human, though they are comparatively large 

 and narrow, each bearing a fifth cusp. The socket of molar 3 

 indicates an equally large tooth, placed well within the ascending 

 ramus of the jaw. The two molars have been worn perfectly flat 

 by mastication, a circumstance suggesting that the canines re- 

 sembled those of man in not projecting sensibly above the level of 

 the other teeth. The weakness of the mandible, the slight pro- 

 minence of the brow-ridges, the small backward extent of the 

 origin of the temporal muscles, and the reduction of the 

 mastoid processes, suggest that the specimen belongs to a female 

 individual, and it may bo regarded as representing a hitherto 

 unknown genus and species, for which a new name is proposed. 



The Authors conclude that the Piltdown gravel-bed is of the 

 same age as the contained Chellean implements, which are not 

 so much waterworn as most of the associated flints. The rolled 

 fragments of molars of the Pliocene elephant and Mastodon are 

 considered to have been derived with the flints from older gravels ; 

 while the other mammalian remains and the human skull and 

 mandible, which cannot have been transported far by water, must 

 be assigned to the period of the deposition of the gravel-bed itself. 

 The remoteness of that period is indicated by the subsequent 

 deepening of the valley of the Ouse to the amount of 80 feet. 



In the Appendix, Prof. Elliot Smith remarks that, although 

 the brain presents a remarkable general similarity to the well- 

 known cranial casts of Palaeolithic man, and especially to those 

 of Gibraltar and La Quina, which are supposed to be feminiue, 

 the cast of the skull here described is smaller and more primitive 

 in form than any of these. The most noteworthy feature is the 

 pronounced goriila-like drooping of the temporal region, due to 

 the extreme narrowing of its posterior part, which causes a deep 

 excavation of its under surface. This feeble development of the 

 part of the brain which recent research has shown to be intimately 

 related to the power of speech in modern man is very significant, 

 especially when we notice that a marked boss (which, as Dr. Smith 

 Woodward described, lends a curiously distinctive form to the 

 brain-cast and skull, when viewed from behind) is making its 

 appearance in precisely the spot where in modern man is developed 

 the mechanism that permits the spontaneous elaboration of speech 

 and the ability to name objects. 



The apparent paradox of the association of a simian jaw with a 

 human brain is not surprising to one familiar with recent research 

 upon the evolution of man. In the process of evolving the brain 

 of man from the ape the superficial area of the cerebral cortex had 

 to be tripled ; and this expansion was not like the mere growth 

 of a muscle with exercise, but the gradual building-up of the most 

 complex mechanism in existence. The growth of the brain 



