Geological Society. 373 



liad formed large cavities in the limestone hill, the falling in of the 

 roof of which produced the shock and attending phenomena. 



The earthquakes in Jamaica in 1692. M. Necker is of opinion 

 were non-volcanic, because there were only subsidences of the 

 ground, and because only water, sand, and gravel were ejected. 



The earthquake in the plain of Bogota, 16th November, 1827, he 

 is tempted to consider non-volcanic, the country being gypsiferous 

 and saliferous ; but he admits that it may have been of a mixed 

 nature, in consequence of the great adjacent volcano of Popa- 

 yan being, at the same time, in activity. The earthquakes on the 

 coast of Chili, he is of opinion, may have a similar origin. 



M. Necker gives a list of earthquakes extracted from Mr. Lyell's 

 " Principles of Geology," and arranges them under the heads — vol- 

 canic, non-volcanic, and of doubtful origin. 



In the first list he includes the earthquakes felt at Ischia. 

 February 2nd, 1S28; Java, 1699, 1772, and 1786; Sumbana, April, 

 1815; Quito, Feb. 4, 1797; Sicily, March, 1693, 1790; Guati- 

 mala, 1773; Kamtschatka, 1737; Peru, Oct. 28. 1746; Iceland, 

 1725; TenerifFe, May 5, 1706; Sorea, (Moluccas) 1693; Lisbon, 

 Nov. 1, 1755. 



.Vow-ro/ra«;c.— Murcia, 1829 ; Lahore, Sept. 1827 ; Lissa, in the 

 Adriatic, 1833; Foligno, Jan. 15, 1832; Cutch, June 16, 1819; 

 Cumana, Dec. 14, 1797 ; the Caraccas, March 26, 1790 ; Calabria, 

 1783 to 1786; Bechstan, 1772 ; and Jamaica, 1692. 



Doiibfful Oric/in.— Bogota, Nov. 16, 1827 ; Chili; Quebec, Dec. 

 1791 ; Nipon, Japan, August 1, 1783 ; and Martinique, 1772. 



Thus, though M. Necker reduces considerably the power of vol- 

 canic agents, yet he is far from denying that a weak volcanic move- 

 ment may be propagated over considerable surfaces ; and he men- 

 tions, in conclusion, the following instances, as not generally known, 

 of probable connexions between earthquakes and volcanic eruptions. 

 The great eruption of Vesuvius, which commenced the 21st of Fe- 

 bruary, 1822, was preceded by an earthquake at Geneva, and in the 

 province of Bugey, in France, on the 19th of February ; and, before 

 the eruption of October of the same year, the environs of Aleppo, in 

 Syria, had been convulsed during the whole of August ; the most 

 violent shocks having taken place the 13th of the same month ; and 

 on the 14th of August an earthquake was experienced at Laybach 

 in Caniiola. On the 19th of February, 1825, the town of St. 

 Maure, in the Ionian Islands, was almost destroyed by an earth- 

 quake, felt also at Corfu and Prevesa. During the night of the 

 20th and 21st of February, 1825, there were several shocks at San 

 Vcit in Carlnthia ; and on the 21st of February, and for five days 

 after, dreadful earthquakes were felt at Alger and its environs. The 

 25th of February, 1828. Vesuvius, which had been very quiet from 

 1822, commenced a new eruption. There were earthquakes at 

 Trieste during the night of the 13th and 14th January, 1828, at the 

 Island of Ischia on the 2nd of February, and all over Belgium the 

 23rd of the same month. Lastly, M. Necker deems it not impro- 

 bable, that the cartliquakes felt in Hungary, Transylvania, Gallicia, 



