138 Transactions. 



tHat tlie 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 sbot ; tbe 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 Eiver. 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 haviiig 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 shoAV 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 sufiiciently 

 near the surface to check the downward flow of the wet shingle. 



Before leaving the subject of the Otira E-oad, 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 



