364 Transactions. — Geology. 



by water dui-ing flood-time almost auyvrliere, but these im- 

 mense blocks cannot have been coaxed or wheedled down by 

 the comparatively small trickle of water which meanders 

 amongst them. The western side of the valley is particularly 

 rich in illustrations of the deposition of rocks by snow. 



To the botanist a field both novel and various is offered, 

 whilst the artist might find scenes of the rarest beauty and 

 grandeur. 



To the entomologist many kinds of insects not met with 

 elsewhere abound. The grasshopper family predominates, but 

 several kinds of butterflies are to be seen. The insects which 

 I have observed at the highest altitudes are a black butterfly 

 {Percnodaimon ^ili^l^o), with yeUow spots on the wings, whose 

 flight is sluggish and heavy; and a black weta {Hemideina), 

 having a body lin. in length, but with hair-like antennae nearly 

 2in. long. These latter insects are found far above the snow- 

 line, and appear to exist where even Hchens are rarely met 

 with. But the ubiquitous blue-bottle {Callipliora) soars even 

 higher, for I have seen these flies at over 9,000ft., in places 

 where the snow-line would be 4,000ft. below. Some very fine 

 green lizards (Xaidtinus) are also to be found in the locahty. 

 I have seen a specimen, I should think, 18in. long. 



Standing at the head of the Murchison Glacier one can 

 read the history of its mar^'ellous conception and growth — 

 from the crystaUine sno^vflake to the dull and absorbent 

 condition, then into the neve, and by gradual infiltration, re- 

 freezing or regelation, and consolidation, into the glacier 

 " gi'anule," and by continued pressm-e into that hard black ice 

 which one meets with in the middle and lower parts of a 

 glacier, laden in lines from well-defined soui'ces with its bur- 

 den of millions of tons of rocks, shed by denudation fi-om the 

 adjacent mountains, and being borne on with slov/ but irresist- 

 ible force to then* resting-places on the lateral or terminal 

 moraines. 



The theory of glacier-motion natura.lly occurs to one in 

 such a locality ; and this subject opens out a large field for 

 scientific observation and thought, wbich it v>-ould be impru- 

 dent to encroach too far upon in a paper of this nature. My 

 own reading and observatioia lead me to think that the only 

 theory worthy of credence is that of gi-avitation and pressm'e 

 fi"om above, and, in some instances, lateral pressui"e through 

 contraction of the bed of the glacier. It has always struck 

 me that the motion of a glacier may be most aptly compared 

 to that of water in the bed of a river, that flows slowly in 

 places, and is broken up and flows more swiftly over places 

 where its bed inclines at a steeper angle from the horizontal. 

 From careful obsei-vations by many men of note, it is well 

 known that over beds inclininfr at the same angle a greater 



