Scientific Intelligence. Geology. 403 



the surface of the copper-ore highly iridescent, then purple, 

 and in the course of a few days grey, the grey crust being 

 covered with metallic copper, deposited in brilliant crystals, 

 and with a slightly greenish soluble salt. This crust resembled 

 grey sulphuret of copper, and increased in thickness after 

 the operation had been continued several weeks. 1 ' The crust 

 on the specimens received from Mr Fox was thin, and the 

 quantity so small, that an exact analysis of it could not be 

 made. But the result of the examination to which it was sub- 

 jected, approached so nearly to that of the Cornish sulphuret 

 as to warrant the conclusion of its being the same chemical 

 compound. The soluble salt was found to be a sulphate of 

 copper and iron, which accounts for the iron that the yellow 

 copper-ore had lost during its conversion into sulphuret. Mr 

 Fox considers that, assuming the grey crust to be the sulphu- 

 ret of copper, as it turns out to be, those results explain why 

 metallic copper occurs in our mines in contact with grey and 

 black copper-ore, and not with the yellow sulphuret of that 

 metal, and likewise why the former is generally found nearer 

 the surface than the latter, and also near cross courses, and in 

 situations where it is most exposed to the action of water, the 

 expelled ferruginous matter being indicated by the " gossan." 

 This usually consists of quartz as well as iron-ochre, &c., and 

 it abounds in copper veins, but not in those of tin. Phil. Mag. 

 3d series, No. 60, p. 171. 



20. Jamesonite from Estremadura, analyzed by Count F. 

 Schajfgotsch. The specimens analyzed were readily cleavable 

 in a direction perpendicular to the axis of the crystals, and 

 with some difficulty in several directions parallel to the axes of 

 the crystals ; Lustre metallic ; Colour dark lead-grey ; Streak 

 blackish-grey ; Hardness a little greater than that of rock-salt. 

 Specific gravity = 5.616 at 19 cent. Lead 39971, Anti- 

 mony 32.616, Sulphur 21-785, Iron 3.627, Bismuth 1.055, Zinc 

 0.121 ; = 99.475. Phil. Mag. 3d series, No. 60. p. 237. 



21. On the Fossil Bones of the Tertiary Formation ofSiinorre, 

 Sansan, fyc. in the department of Gers, and on the recent dis- 

 covery of a Jaw of a Fossil Monkey. An extremely interesting 

 accumulation of fossil bones was discovered about two years ago 

 by M. Lartet in the department of Gers, in the south-west of 



