14 Transactions. 



rises to a height of over 6,000 ft., and covers an area of about 

 ten square miles. The mountain is composed of massive olivine 

 containing disseminated chromite. The latter occurs in much 

 greater proportion than at Dun Mountain. The peridotite is 

 flanked on two sides by belts of serpentine, which separate it 

 from the adjacent slates and sandstones of supposed Paleo- 

 zoic age. Near the contact with the sedimentary rocks it is 

 often so highly charged with chromite as to form compact 

 bodies of ore. No deposits of chromite are known in the 

 serpentine, but they may possibly exist, as the country is still 

 practically unexplored. 



Nickel-iron. 



The sands in the streams which drain the Eed Mountain 

 serpentine area yield small quantities of the rare nickel-iron 

 alloy awaruite, discovered by Skey in 1885, * and afterwards 

 found in situ in the serpentine.! 



Since the discovery of awaruite nickel-ore alloys have been 

 found in several places, most notably in gold-bearing sands 

 associated with chromite in Elvo Eiver, Biella, Piedmont, 

 Italy ; in sands derived from serpentine in Josephine County, 

 Oregon ; in the Fraser Eiver, British Columbia, associated 

 with chromite ; and in Smith Eiver, Del Norte County, 

 California. 



Copper. 



The association of copper and chromite in the serpentines 

 at Dun Mountain has already been mentioned. Native copper 

 is found in serpentine in Cornwall, New South Wales, New 

 Caledonia, and other parts of the world. 



Large masses of native copper associated with silver are 

 found in amygdaloidal diabase at Lake Superior. 



In 1879 Professor S. H. Cox| discovered in the Manukau 

 district a number of dykes of andesite which near their borders 

 were found to contain small scattered grains of native copper. 

 The dykes are intruded in volcanic breccias of probably 

 younger Miocene age. 



Platinum-metals. 

 Platinum has only been found in a few cases in the matrix 

 in situ. In the Ural Mountains it occurs as grains in perido- 

 tite, serpentine, and olivine-gabbro. The bed-rock of the 



* W. Skey, Trans. N.Z. Inst. vol. xxiii, 1885, p. 401. 



t G. H. Ulrich, " On the Dincovery, Mode of Occurrence, and Dis- 

 tribution of the Nickel-iron Alloy Awaruite on the West Coast of the 

 South Island of New Zealand," Quart. Jour. Geol. Soc. London, vol. xlvi, 

 p. 619. 



I S. H. Cox, "Geology of Cape Rodney," N.Z. Geol. Reports and 

 Explorations, 1879-80, p. 27. 



