287 



reached, many men seem to get tired of good healthy work, and instead of 

 exploring fresh fields go over the old, and keep magnifying minor differences 

 into groups of families, to the complete confusion of everything ; forgetting 

 that the great aim of all science is simplicity, and the more simjjle a science 

 the grander and nobler it is. 



Art. LII. — On a New Form of Iron Pyrites. By E. H. Davis, F.C.S., F.G.S. 



(With Illustrations.) 



[Read before the Wellington Philosophical Society, September 17, 1870.] 



Iron pyrites has long been known as a dimorphous mineral, occurring crys- 

 tallized in the tesseral and rhombic systems ; the latter variety, called marcasite, 



o 

 occurs as a right rhombic prism — oo P 106° 5', brachydome |- P °o 136° 54', 



brachydome P oo 80-20 and a macrodome P co 64° 54' combined. The other 

 form is common in cubes co co , octahedron O, and sevei'al semitesseral forms, 



cx02 



the pentagonal dodecahedron — g-^ the hemihedral form of the tetrakishexa- 

 hedron, rarely tetrahedi-al ; a common combination is that of the pentagonal 

 dodecahedron with the octahedron, the faces of the latter replacing the 

 trigonal angles of the dodecahedron. Macles are common, but are not material 

 to the present purpose. 



Plate XX YI., fig. 7., is a new form from the Chatham Islands. The 

 lustre, specific gravity, and hardness, are the same as the common varieties ; 

 the system is oblique, nearly isomorphous with felspar, but having the 

 clinodiagonal longer; the faces, which are smooth and brilliant, are oo P prism (P), 

 OP clinopiuacoid {M), P hemipyramid (ct), nVao hemidome (d), (?iPco ) clino- 

 dome {n). 



The thick lines show where the crystal is cut ofi". 



Art. LITI. — RemarTcs on the Resemhlance of the Country in the neighbourhood 

 of the Dun Mountain, and Wairoa Go^ge, to the Mining Districts of 

 Queensland and Auckland. By W. Wells. 



[Bead before the Nelson Association for the Promotion of Science and Industry, 



Ap)ril 6, 1870.] 



In bringing the subject of the present paper before the Association, I will at 

 once state that I am indebted for the facts contained in it partly to my own 

 observation, but more particularly to communications received from Dr. Hector, 

 Mr. T. P. Hackett, and, latterly, to a very able report on the Pockhampton 

 gold-mining district in Queensland, by Mr. Daintree, the Government Geologist 

 of that colony. 



