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It was whilst staying in Quintero, Chile in November 1822 that Maria Graham experienced the series of earthquakes which would form the subject of her paper to the Society.
Although claiming to be a simple extract from her journals, her text was in fact a carefully condensed, precise report on the time, duration and intensity of the quakes, with first-hand observations of the resulting phenomena.
One of the most striking descriptions was of the uplift of land which exposed the ancient sea bed:
“It appeared on the morning of the 20th that the whole line of coast from north to south, to the distance of above 100 miles, had been raised above its former level. I perceived from a small hill near Quintero, that an old wreck of a ship which before could not be approached, was now accessible from the land, although its place on the shore had not been shifted.
“The alteration of level at Valparaiso was about 3 feet, and some rocks were thus newly exposed, on which the fishermen collected the scallop shell-fish, which was not known to exist there before the earthquake. At Quintero the elevation was about 4 feet.
“When I went to examine the coast...although it was high water, I found the ancient bed of the sea laid bare and dry, with beds of oysters, muscles, and other shells adhering to the rocks on which they grew, the fish being all dead, and exhaling most offensive effluvia.
“I found good reason to believe that the coast had been raised by earthquakes at former periods in a similar manner; several ancient lines of beach, consisting of shingle mixed with shells, extending in a parallel direction to the shore, to the height of 50 feet above the sea.”
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