Mannerixg. — On the Murchison Glacier. 3oo 



Olivine Gabbro. From Bluff Hill. 



A rather coarse-grained, dark-grey, granular rock. Specific 

 gi-avity = 2-916. 



Scctio7i. — Plagioclase iu broad laths and plates composes 

 about one-half of the rock ; the other half is ferro-magnesiau 

 minerals. Diallage is allotriomorphic, pale-purple iu colour, 

 and forms ophitic plates enclosing the plagioclase and ohvine : 

 iu places it is decomposed into chlorite. The ohvine is colour- 

 less, in rounded crystals, much decomposed on the margins 

 and in cracks: it is not abundant. Magnetite is in small 

 quantity. There is also a httle pyrites. 



Greexstoxe -^sh. From Green HiUs. 

 • Fine-grained, dark-green rocks, sometimes laminated with 

 finer and coarser materials. These rocks are the diabasic ash 

 of Mr. Park. Thin sections show them to consist of minute 

 angular fragments of feldspar, much decomposed, but chiefly 

 orthoclase, abundantlj" infiltrated with chlorite. There is no 

 quartz. P\Tntes occurs commonly. 



Art. XXXVI. — On the Murchison Glacier. 

 By G. E. MaxxebdvG. 



■ Bead before the Philcsophical Institute of Canterbury, 4lh September, 



1S90.: 



Plate XXXY. 



INTRODUCTORY. — SoME EEilAEKS OX THE PrLSCLPAE Xew 



Zealand Glaclebs. 

 It is a strange fact that the average Xew-Zealander knows but 

 little of the physical features of his own country. It is strange 

 that he knows still less of its great mountains cind glaciers, 

 and of all the marvels of nature wliich immediately surround 

 them ; but it is stranger yet that there should lie hidden for 

 so many years a glacier of such extent and importance as the 

 Murchison, whose ice was trodden for the first time in the 

 summer of last year-. It is also interesting to note that 

 almost all scientific explorations and records concerning our 

 essentially alpine mountains have been made by foreigners or 

 visitors to oiu* shores. 



The principal Xew Zealand glaciei-s on the eastern side of 

 the main range are situated iu the very heart of the Southern 

 Alps, and comprise those at the head-waters of the Eangitata 

 River— namely, the Havelock, Clyde, and Lawrence Glaciei-s ; 



