SiGERSON — On the Physical Geography of Ireland. 11 



whose eruptions are ckronicled, are situated, or arise in limestone dis- 

 tricts. It is known that the strata of limestone may, and often do 

 include subterranean reservoir's and channels of water ; an instance of 

 the latter is found in the case of the underground river near Cong. 

 With, perhaps, an exception, the lakes found in districts from which 

 limestone is absent, as Lough Foyle, Belfast Lough, are loughs which 

 communicate with the sea, and may have received their waters from 

 it. I now proceed to give parallel cases for those mentioned in the 

 Irish Annals. 



Eruptions of lakes constitute the first category of observed pheno- 

 mena. The Irish Annalists chronicle the eruption or bursting forth 

 of the following lakes : — 



A. M. 2532. The eruption of Loch Conn and Loch Techeat. 



A. M. 2533. The eruption of Loch ]\Iask. 



A. M. 2535. Loch Laighline sprang forth. The eruption of Loch 

 Eachtra also. 



A. M. 2859. Loch Derryvaragh and Loch Enuell sprang forth, and 

 about this period sprang forth Loch Gall and Loch Earner. 



A. M. 3506. Eruption of the following lakes : Cimbe, Buadaig, 

 Baad, Ren, Einnmaige, Grreine, Riach, Da-Chaech, and Loch Laegh. 



A.M. 3581. Eruption of nine lakes: Uair, larn, Ce, Sailean, 

 Ailleann, Feabail, Gabair, Dubloch, and Loch Daball. 



A. M. 3790. Death of the monarch Aengus. These are the lakes 

 which burst forth in his time : Aenbeite, Saileach, and l!^a-ngasan. 

 'A. M. 4694. Loch Melvin burst forth over the land in Cairbre. 



Parallel cases. These have occm-red usually but not necessarily 

 coincidently with earthquakes, though the shock may not have been 

 felt. 



The cases recorded are compiled from Mallet's catalogue : — 



A. D. 1790. Terra !N"ova, Sicily. The gradual sinking of a piece of 

 ground, three Italian miles in circumference, to a depth of thirty feet, 

 took place. Erom fissures in the soil burst forth vapours, petroleum, 

 sulphur, hot water, and finally a stream of salt mud. 



A. D. 1790. South America. A piece of forest land, resting on 

 granite between the villages of San Pedro de Alcantara and San Fran- 

 cisco de Aripao sank eighty or one-hundred feet, and produced a lake 

 four-hundred toises in diameter. 



A. D. 1792. The ground opened about Tureguraqua, and lakes 

 were found. 



A. D, 1802. South America, A piece of ground, one-hundred feet 

 long and forty feet wide sank down, and a pool of water appeared in 

 its stead. 



A. D. 1805. Earthquake at J^aples. At Bojano a lake made its 

 appearance. 



A. D. 1806. Siberia. A mountain, distant twelve versts from 

 Krasnojarsk was replaced by a lake of three hundred feet in circumfe- 

 rence, and one-hundred and eighty feet in depth, in some places ; the 

 water in which had the taste and smell of sulphur. 



