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XLL— ON THE ANTIPODAL KELATIONS OF THE NEW 

 ZEALAND EARTHQUAKE DISTRICT OF 10th JUNE, 

 1886, WITH THAT OF ANDALUCIA OF 25th DE- 

 CEMBER, 1884. By J. P. O'REILLY, C. E., M. R. I. A., 



Professor of Mining and Mineralogy, Royal College of 

 Science, Dublin. (Plate IX.) 



[Read, January 19, .1887.] 



In an address delivered before the Royal Geological Society of 

 Ireland on the gaseous products of the Krakatoa Eruption, I took 

 occasion to call attention to the antipodal relations of Java with 

 the north-west coast of South America, and argued from the fact 

 of there being, in this case, two districts of marked seismic activity 

 directly antipodal, that in cases where such relations exist, marked 

 seismic action may be expected to manifest itself. I had, in ano- 

 ther Paper read before the Royal Irish Academy 14th Novem- 

 ber, 1881, argued that in centres affected by earthquake action 

 the points of greatest activity generally lie on coast lines, or on 

 the boundary lines of geological formations : this was subsequently 

 illustrated by an earthquake map of Great Britain and Ireland,, 

 annexed to the catalogue of earthquakes having occurred in these 

 countries, submitted to the Royal Irish Academy, 28th April, 

 1884. 



The antipodal relations above referred to, as also the connexion 

 of earthquakes therewith, and with coast lines and coast line di- 

 rections, have recently received a remarkable illustration in the 

 great earthquake of Andalucia of Christmas, 1884, and January r 

 1885, taken in connexion with the earthquakes and volcanic erup- 

 tions which occurred in June last in the Northern Island of New 

 Zealand. 



In order to show these relations between the two countries in 

 question, I have prepared a map (Plate IX.) presenting the projec- 

 tion, of the antipods of the northern island and of part of the middle 

 island of New Zealand, on the map of Spain. This projection is 

 shaded, and the zone of maximum volcanic intensity in the northern 

 island is represented by cross-hatching, being limited in one direc- 



