44 Reports and Proceedings — Mineralogical Society. 



The ascending ramus is comparatively wide, with extensive insertions 

 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 resembled those of man 

 in not projecting sensibly above the level of the other teeth. The 

 weakness of the mandible, the slight prominence 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 be 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. 



III. — Mineralogical Society. 



Anniversary Meeting, November 12, 1912. — Dr. A. E. H.Tutton,P.Pi,.S., 

 President, in the Chair. 

 Professor W. J. Lewis : Ilmenite from the Lengenbach Quarry. 

 Embedded in the dolomite was found a minute crvstal, irregular in 

 habit, showing the forms 110, 101, 100, 112, 111, 275. The best 

 readings were obtained from pairs of faces of 101 and between them 

 and faces of a prism, the corresponding angles being found to be 64° 47' 

 and 57° 33' respectively. —Professor W. J. Lewis : Multiple Twin of 

 Cassiterite. Threefold twiniiing is well and regularly developed on 

 opposite sides of the ciTstal, which consists of two main portions 

 with twin axes all in one plane, and the triplets so formed are con- 

 nected together in a somewhat irregular way. Further, some of the 

 individuals are twinned along pyiamid faces inclined to the general 

 plane so that the back of the crystal is unlike the front. — Arthur 

 Russell : An account of the Minerals found in the Virtuous Lady 

 Mine, near Tavistock. The following species were met with : 

 chalj'bite, in pseudomorphs after fluor and barytes, termed respectively 

 'boxes' and ' slippers' by the miners; marcasite in sheaf-like aggre- 

 gates; mispickel in two modifications; anatase, on one crystal of 

 which was found a small crystal of brookite, the only one seen by 

 the author from this locality. — Dr. A. Hutchinson : Some Graphical 

 Methods in Crystallography and Crystal Optics. Diagxams of ex- 

 pi'essions involving sines, such as sin E= /3sin V, are much simplified 



