NICKEL-IEON ALLOY AWAKIJITE OF NEW ZEALAND. 625 



Humboldt Mountains (about 6| miles S. by W. from the junction 

 of the Barrier Creek with the P5'ke E-iver). What leads to this 

 conclusion is, that Messrs. Henderson and Batement saw con- 

 spicuously bare and red-coloured mountains and ridges (like those 

 of the Eed-Hill Kange) further southward, near Lake-Harris Saddle, 

 the watershed between the Route Burn (a tributary of the Dart 

 Eiver falling into Lake Wakatipu) and the Hollyford Eiver ; and 

 that they found boulders of olivine rock and serpentine in one of 

 the creeks rising near that saddle and falling into the Hollyford 

 Eiver. Still another important proof is that at the head of the 

 Caples Eiver (about 22 miles S. of the junction of Barrier Creek 

 and Pyke Eiver) there occurs in massive outcrops a dark-green ser- 

 pentine, closely resembling that of the Eed Hill and enclosing 

 veins and bunches of compact talc (steatite). 



With regard to the geological relations of the peridotite and 

 serpentine rocks to the enclosing crystalline schists, there can be no 

 doubt, according to Messrs. Henderson's and Batement's observations, 

 that the former are intrusive through the latter; several places 

 having been observed by them where the strike of the schists was 

 right against the peridotite and serpentine outcrops. 



Judging from examination of the specimens available, the unal- 

 tered peridotite, in its petrographic character, is always holocrystal- 

 line, and its main constituents (olivine and enstatite) are allotrio- 

 morphic. It shows, however, various modifications. On the Eed 

 Hill it conforms toWadsworth's species " saxonite," is of iight-greenish 

 colour, and varies from coarse to fine granular in texture. The 

 olivine and enstatite vary much in relative proportions ; while in 

 some specimens the former greatly predominates over the latter, 

 in others the reverse is the case. This can be well seen on the red- 

 weathered surface of the rock, which shows the enstatite in out- 

 standing angular particles of irregular size and form ; the olivine 

 once connecting them having been decomposed and removed. Chro- 

 mite, though in some parts abundant, appears on the whole rather 

 sparingly distributed throughout the rock; partly and more fre- 

 quently in larger and smaller grains of irregular contour? ; partly in 

 small perfect octohedrons. These grains and crystals are easily 

 identified by their lustre, together with the green colour imparted 

 by the powder to the borax bead. Several specimens with pre- 

 dominating enstatite show on the surface light to dark emerald-green 

 portions which do not seem to occur in the interior of the rock, as I 

 found on cutting two such pieces in various directions. Although 

 they seem at first sight to belong to a difi'erent species of pyroxene 

 (diallage), closer examination proves them to be so similar in lustre 

 and structure to the associated, common, yellowish or brownish 

 enstatite, that I suppose they most probably represent only a green- 

 coloured variety of the latter. Owing to the failure of several attempts 

 in preparing thin sections showing the green mineral, through the 

 latter unfortunately breaking away or quite disappearing during 

 the grinding, and not liking to destroy any more of the remaining 

 specimens, reserved for transmission with this paper, I have not 



