116 EARTHQUAKES IN THE EIGHTEENTH CENTURY. [Ch. XXIX. 



as latent as in parts of Glreat Britain now occupied exclusively 

 by ancient marine formations. 



Extent of the area convulsed. — The convulsion of tlie earth, 

 sea and air extended over the whole of Calabria Ultra, the 

 south-east part of Calabria Citra, and across the sea to 

 Messina and its environs ; a district lying between the 38th 

 and 39th degrees of latitude. The concussion was percep- 

 tible over a OTeat part of Sicily, and as far north as Naples ; 

 but the surface over which, the shocks acted so forcibly as to 

 excite intense alarm did not generally exceed 500 square 

 miles in area. That part of Calabria is composed chiefly, 

 like the southern part of Sicily, of argillaceous strata of great 

 thickness, containing marine shells, sometimes associated 

 with beds of sand and limestone. Tor the most part these 

 formations resemble in appearance and consistency the Sub- 

 a*pennine marls, with their accompanying sands and sand- 

 stones ; and the whole group bears considerable resemblance, 

 in the yielding nature of its materials, to most of our tertiary 

 deposits in France and England. Chronologically considered, 

 however, the Calabrian formations are comparatively 



lern date, often abounding in fossil shells referable to 

 species now living in the Mediterranean. 



We learn from Vivenzio, that on the 20th and 26th of 

 March, 1783, earthquakes occurred in the islands of Zante, 

 Ce]3halonia, and St. Maura ; and in the last-mentioned island 

 several public edifices and private houses Avere overthrown, 

 and many people destroyed. 



If the city of Oppido, in Calabria Ultra, be taken as a 

 centre, and round that centre a circle be described, with a 

 radius of 22 miles, this space will comprehend the surface 

 of the country which suffered the greatest alteration, and 

 where all the towns and villages were destroyed. The first 

 shock, of February 5, 1783, threw down, in two minutes, the 

 greater part of the houses in all the cities, towns, and villages, 

 from the western flanks of the Apennines in Calabria Ultra 

 to Messina in Sicily, and convulsed the whole surface of the 

 country. Another occurred on March 28, with almost equal 

 violence. The granitic chain which passes through Calabria 

 From north to south, and attains the height of many thousand 



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