O'Eeilly — On Localities marked by Earthquakes. 503 



LXXII. — On a Relation to be established BET"nrEEN Coast-line 

 Directions eepeesented by Geeat Cikcles on the Globe anb 

 CEEiAiN Localities in Etteope maeked by feequency of Eaeih- 

 auAKES. Ey Joseph P. O'Reilly, C.E., Professor of Mining and 

 Mineralogy, Eoyal College of Science, Dublin. 



[Eead, November 14, 1881.] 



Foe the student of Geology no phenomena of !N'ature present a wider, 

 more interesting, or more important field of study than Earthquakes. 

 So sudden, so terrible in their effects, so difficult to observe, so mys- 

 terious in their causes (even in the present advanced state of knoTV- 

 ledge), and therefore so insufiiciently studied, every branch of science 

 can find in them matter for observation and study second to none in 

 importance. It might seem, therefore, that a complete, continuous, 

 and systematic record of such events would be deemed indispensable 

 for the progress of the natural sciences ; and such a record we possess 

 in Mallet's P»,eport and Catalogue of Earthquakes up to 1850, pub- 

 lished by the British Association, but for the subsequent years it is to 

 be regretted that we have no continuous catalogue in English, such as 

 those of Professors Perrey and Euchs in France and Germany. 



That this is really a want must be evident from the interest excited 

 by the increasing fi^equency and intensity of earthquakes in Central 

 Europe, by the manifest desii-e to collect more precise and extended 

 information as regards their occurrence, and by the admitted in- 

 sufficiency of the theoretical views in vogue as regards their causes. 



The records of Professors Perrey and Fuchs, with difficulty acces- 

 sible in Great Britain, are yet of the greatest value, and their exami- 

 nation suggests the possibility and the desirability of bringing into 

 more intimate relationship earthquakes, as phenomena, which are 

 apparently quite independent, and have up to the present been only 

 brought into connexion from the point of view of contemporaneity. 



Yet the dependency existing between volcanic action and earth- 

 quakes is fully admitted ; moreover, there is recognised a well- 

 established connexion between volcanoes and great lines of jointing, 

 more especially sea coast-lines. It is therefore reasonable to assume 

 that a similar connexion may be found to exist between these and 

 earthquakes — that is to say, sea coast directions and lines of main 

 jointing being recognised as the loci of volcanic actions, so evidently 

 connected with earthquakes, should there not, consequently, exist 

 some relation between these same directions, as representing lines of 

 main jointing and localities markedly affected by earthquakes, far 

 apart though they may be geographically? 



In the present memoir I endeavour to establish such a connexion, 

 parting from the Theory of Coast-lines Correlation, submitted to the 

 British Association in 1878 (Dublin), and subsequently published by 

 the Eoyal Irish Academy in its Transactions (IS'ovember, 1879). In that 



R. I. A. PROC, SER. II. VOL. III. SCIE>-CE. 2 U 



