8iGERS0N — On the Physical Geogra-phy of Ireland. 9 



Erne district, to which. I drew attention in a former paper, it appeared 

 to be highly probable, that in these lines we had indications of nieso- 

 seismal areas. Their directions seem to point out the directions of 

 seismic energy, in the most ancient days of onr history. It has been 

 frequently found, where noted in latter times, to run in the directions 

 of those lines. The apparent change from a vertical to an oblique 

 direction, coincidently with the chronicled change from the first great 

 group to the second group of phenomena, tends to confirm the state- 

 ments of our annals, as far as they relate to remarkable natural events. 

 That being so, it next became requisite to see whether earthquakes 

 had been known to occur in Ireland; and necessary to ascertain 

 whether such occurrences as those chronicled were such as seismical 

 force would produce, and alone produce. 



"First : Earthquakes in Ireland. 



In 1820, the shock of an earthquake was felt in Cork and neigh- 

 bouring towns. 



In 1534, the Anglo-J^orman chronicles, state that an earthquake 

 was felt in Dublin. The Four Masters make no mention of it. 



In 1490, according to the Four Masters, " There was an eruption 

 of the earth (Maidm-talman) by which a hundred persons were de- 

 stroyed, among them the son of Manus Crossagh O'Hara. Many horses 

 and cows were also killed by it, and much putrid fish were tlirownup, 

 and a lake in which fish is now caught, sprang up in the place." 



In 1452, it is related, that the Liffey was dry for over two miles. 

 The Four Masters say: "A very wonderful presage occurred in this 

 year, some time before the death of the Earl (of Kildare), namely part 

 of the Liffey was dried up, to the extent of two miles." [Although 

 this does not prove the occurrence of an earthquake, it may indicate 

 seismical action, as several such phenomena are on record, all more or 

 less closely coincident with the occurrence of earthquakes near or at 

 a distance.] 



In 1266, mention is made by Anglo-Xorman writers in Ireland of 

 an earthquake, which is stated to have been felt in all parts of Ireland. 

 The Four Masters, however, do not chronicle it. 



In 1191, the river of Galway (according to the Annals of 

 Kilronan) dried up, and a hatchet and spear were found in its bed. 



In 1178, the same river, the Four Masters relate, was dried up 

 for the period of a natural day ; all the articles that had been lost in 

 it from remotest times, as well as its fish, were collected by the in- 

 habitants. O'Flaherty, in his account of lar-Connaught, states, that 

 ancient annals describe the river as having dried up from Friars' Isle 

 (in the lake whence it issues) to the sea, from midnight till noon. It 

 seems probable that there must have been an upheaval of the bed 

 to account for such a phenomena.*' 



* In several cases where earthquakes have boen recorded in recent times, as in Mr. 

 Mallet's catalogue, the temporary drying up of rivers has also been observed to occur ; 

 sometimes the connexion may not be considered quite proven, as when, in 1785, the 



R. I. A. PROC vol.. II., SER. 11., SCIKNCE. C 



