92 
GEOLOGY. 
which involved a great loss of time. If, therefore, I have been 
unable to obtain more extended results than those detailed in this 
report, it must not be attributed to want of energy or per¬ 
severance on my part, but solely to the manifold difficulties under 
which I laboured, and which prevented me from carrying my 
researches further than I have. 
In the Howard, under the drift formation, small seams of lignite 
occur, similar to those found near Nelson; I did not see them in 
.situ, but I found large pieces lying upon the shingly banks of 
that river, evidently brought down during heavy freshes. The 
granitic zone between the Howard and the western foot of Mount 
Murchison is ten miles broad, and as I passed across it in its 
whole breadth, I had an opportunity of obtaining a very good 
section. The amphibolite occurs, not only in small intercalated 
masses, but often forms mountains of considerable size, as, for in¬ 
stance, Mount Maclean. 
Here and there I found the granite charged with needles of 
tourmaline, whilst in other places it was intersected by large veins 
of pegmalite and graphic granite, which latter was of a really 
beautiful structure. Mount Murchison, which I ascended, has 
all the characters of a true granitic mountain. On its rounded 
dome-shaped north-western top, rocking-stones and tables were 
not wanting, whilst the middle and south-eastern peaks exhibited 
conspicuously the great power of the atmospherilies in a country 
where, during part of the year, all the mountains above 4.000 
feet in height are regularly covered with snow; this, partly melt¬ 
ing during the sunny days, is often re-frozen during the nights, 
forming ice in the fissures of the rock, which, in their polyhedric 
clefts, offer ample opportunity for disruption. 
The same process continues, although on a smaller scale, in 
others.besides the winter season, the condensation of the clouds 
and mist creating ice, the greatest agent for the destruction of 
rocks, during the lower temperature of the nights. Heavy rains 
bring down the detritus, which has formed, by attrition upon 
the surface of the rocks, many deep valleys on all sides of the 
mountain. It is astonishing indeed to see on Mount Murchison 
how very narrow the ridge is which connects its various peaks, 
and how abruptly both sides fall for 1,500 to 2,000 feet into deep 
and narrow gorges, with equally abrupt and steep spurs lying 
between them. As such narrow ridges become more worn down 
every year, the formation of pyramidical peaks or needles will be 
easily understood. I often looked with astonishment at the small 
rivulets, which have worked deep and broad channels, to which 
their volume of water bore no apparent proportion, through or 
parallel with high mountain chains ; and in this again we may see 
a convincing proof that nature, in order to produce great effects, 
often uses only small but continuously working means, the results 
obtained being far more extensive than any which would accrue 
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