WellmgtoJi Philosophical Society. 509' 



had been broken and shifted 8 feet 6 inches to the east of the line in 

 which they originally stood. Next it was shown that the evidences con- 

 sisting of slips and earth-rents are confined to a narrow belt of country 

 extending S.S.W. from the east corner of the Hanmer Plain to the Upper 

 Hope Valley, abreast of and about six miles to the north of Lake Sumner, 

 in the Hurunui Valley. Beyond this point to the westward the line of 

 dislocation was not examined. All these rents and fractures lie along a^ 

 line of previous earthquake disturbance, the old fractures indicating this 

 being traceable on tiie surface where the line does not run along river- 

 beds, liable to be flooded and leave the surface shingles rearranged. The 

 eastern continuation of this line of old fractures caused by earthquakes 

 was described as extending to the eastern base of i\Iount Fyffe, near 

 Kaikoura. Glynn Wye was described as being the point on this line at 

 which the most violent disturbance of the surface took place ; while 

 Westport, GO miles to the north, Cliristchurch, 65 miles to the south, 

 and Kaikoura on the east coast and Hokitika on the west coast, were the 

 limits to which the earthquake extended as a shock violent enough to do 

 damage to buildings, &c. Mr. McKay said that, while not touching the 

 question what the primal cause of earthquakes may be, he felt sure that 

 the Amuri earthquakes, in as far as they were expressed at the surface 

 and had been studied by him, were due to crushing movements along 

 the old earthquake-line ; and he went on to show that in the northern 

 part of the South Island, and, indeed, throughout the islands of New 

 Zealand, there are many old faults, showing a great vertical displace- 

 ment, running coincident with earthquake -rents opened but recently, 

 though not for the first time. The whole of the northern part of the 

 South Island, it was stated, was being elevated, and a series of parallel 

 fractures gave relief to the resulting strain, which relief, at the moment 

 of its happening, produced the earthquake. 



Sir James Hector considered that this paper, as a simply-told nar- 

 rative of the observed facts, would become classical in the literature of 

 earthquakes, and he complimented the author on its excellence. He did 

 not quite agree with all the author's deductions, however. The mere 

 linear extension of fault-lines did not determine a liability to earth- 

 quakes. There must be a lateral stress or condition of strain in some 

 part of the fault-line. As he had pointed out last year, a violent con- 

 cussion might originate from a slickenside surface in a fault. He quite 

 agreed that in this particular case there was nothing to connect this 

 shock with volcanic action, present, past, or future. It seemed to be a 

 localised fault-movement, no doubt produced by the jar of a wide-spread- 

 ing earthquake-shock of the ordinary mild character. 



Mr. i\IcKaj% in reply, stated that we could only deal with what was 

 open to observation. The facts went to prove that from some point not 

 far from Glynn Wye the force of the shock diminished in all directions ; 

 and practically there or thereabouts the centre of the disturbance must 

 be placed. As to the influence of the great faults, it mattered little 

 whether the earthquake produced the faults or the faultings were the 

 cause of the earthquake — both were effects of a greater movement behind 

 either or both ; but, as the faults and earthquake-rents were in this dis- 

 trict on the same lines, the earthquakes were always most severe in the 

 near vicinity of those lines. Mr. McKay said he spoke not of the nume- 

 rous lesser faults that are to be found all over the country, but of the five 

 or six greater faults whose movements have stamped with peculiarity 

 the physical features of the whole district. 



Sir James Hector exhibited a specimen of Alumite from 

 Australia, with the alum obtained from it. He explained that 

 it had been discovered by Mr. J. H. Cox, late Assistant- 

 Geologist. 



