# Page:A Treatise on Geology, volume 2.djvu/255

1783, the Lisbon earthquake of 1755, the Chilian earthquakes of 1822 and 1835. In 1822, according to Mrs. Graham, the Chilian coast was agitated by a movement which extended in length 900, 1000, or perhaps 1200 miles (including Copiapo and Valdivia), and raised the whole line of coast for a distance of 100 miles; at Valparaiso 3 feet; at Quintero 4 feet; the greatest movement being about 1 5 miles N. E. of Valparaiso: the beds of oysters and other shells were raised clear to the surface. The whole region between the Andes and a line far out in the sea is supposed to have been permanently raised, 2, 3, or more feet (in the interior the elevation is said to have reached even 7 feet). The area under which, ashore, the earthquake extended, is estimated at 100,000 square miles.[1] If, as Mr. Lyell supposes, the whole of this vast area was raised, and the elevation be taken at 1 foot on the average, the whole augmentation of the earth's diameter caused by it will be $\scriptstyle \frac 1{4000}$th part of that which we attribute to the whole mass of visible volcanic accumulations on the surface. It is unnecessary to re-open the discussion of the accuracy of the data above assumed, because in 1835 similar phenomena happened on another part of the same coast.