188 * "Transactions. 
that the country has been starred, just as a mirror is starred by a violent blow, 
or as in rock blasting a set of radiating fissures is sometimes produced by a 
single shot; the other running parallel to the axis of the foldings of the 
strata, or rather following a compound course, partly on the lines of strike, 
and partly on the lines of the joints of the strata, like a line struck diagonally 
across a chess board, but following the sides of the squares, and giving to 
the cliffs which bound these valleys a peculiar rectangular appearance, 
resembling ruined masonry on a gigantic scale. 
Now, it will be observed that, with the exception of that of the Hurunui, 
none of the radiating valleys run directly across the main chain, which, at 
the heads of the Rakaia and Waimakariri, stands up like a wall, barring all 
further progress. Haast’s Pass, the lowest and probably the easiest of all, 
does not extend across the northern branch of the chain, but leads to the 
coast by following the westerly course of the Haast River. Arthur's Pass 
does not, as it were, cross the range in a direct line, as does that by the 
Hurunui, but leads along it from one radiating valley to another; the 
Waimakariri and the Teremakau overlapping each other to the extent of 
about twenty miles. 
Thus it will be understood that these three passes occur under three 
distinct sets of conditions, Haast’s Pass, at the head of the Wanaka Lake, 
is both in the line of one of the great radiating valleys, and also in the 
direction of the axis of the great foldings of the strata, these two causes in 
combination having formed an unusually low gap in the mountains. The 
Hurunui Pass, on the other hand, is one of the fractures running directly 
across the range, whilst Arthur’s Pass is simply a fissure parallel to the 
planes of stratification, from which the rock, already bruised and shattered 
when the surface of the country was crushed up into the huge fold- 
ings before referred to, has been gradually removed by glacial action, 
and by the weathering process constantly going on over the whole face 
of nature. 
The depth to which the great valleys have been filled up with shingle 
and debris, may be inferred from the interesting sections, prepared by Dr. 
Haast, of the comparative fall of the Canterbury rivers, and from those pre- 
pared by the Provincial Engineer in connection with the Otira Road. 
These sections show that the river-beds form beautifully regular curves 
from their sources to the rock-bound gorges through which they issue to 
the plains, which would not be the case if the rock bottom were sufficiently 
near the surface to check the downward flow of the wet shingle. 
Before leaving the subject of the Otira Road, I would call your attention 
_ to the great value of the aneroid barometer as an instrument for ascertain- 
. ing altitudes. During the Provincial Engineer's explorations of the West 
