774 



GEOLOGY. 



the lowest on a level with high water, the highest about forty feet above it. The rise of 

 the land, in general gradual, and not by paroxysmal effort, is indicated by most of the 

 phenomena in question, of which it is impossible certainly to assign the date, though 

 referable to the modern epoch. It seems, indeed, a well-established fact, that various 

 parts of our present continents are subject to vertical movements, either of elevation or 

 depression, or of both alternately, and that in districts not known to have been visited 

 in the historic period by the action of earthquakes, or of volcanic agency in any form. 



The oscillation of Norway and Sweden, rising in the northern and sinking in the 

 southern parts, some points of the coast showing no vertical movement, was first affirmed 

 by Celsius upwards of two centuries ago, and has been investigated with great ability by 

 Von Buch and Mr. Lyell, the latter a sceptic as to the fact, till a personal examination of 

 the country satisfied him of its, correctness. From Gottenburg to Tornea, and from 

 thence to the North Cape a distance of more than a thousand geographical miles the 

 country appears to have been raised up from 100 to 200 feet above the level of the sea. 

 The breadth of the region thus elevated is not known, and the rate at which the land 

 rises varies in different places. In some sites it has been estimated at four feet in a cen- 

 tury. The evidence that such a movement is taking place, is derived from the measure- 

 ment of the height of landmarks above the sea at various intervals, and from immense 

 deposits of marine silt, containing the shells of mollusca now living in the Baltic, being 

 found at the elevations named, with the barnacles attached to the rocks. One of these 

 beaches, six miles from the present shore, and in some parts four or five hundred feet 

 above the sea, may be traced for a great distance along the Trondheim fiord ; while a large 

 stone near Trelleborg, marked by Linngeus in 1749, is now a hundred feet nearer the 

 shore than in his time. Points of elevation occur distinctly on the coast of Sweden 

 between Calmar and Gefle, while the coast of Schonen is gradually subsiding. No traces 

 of volcanic action are known to exist in these countries, nor have they ever been the seat 

 of earthquakes during the historic era, nor would such paroxysmal events explain the 

 phenomena of gradual elevation and subsidence. The oscillation of the coast of the bay 

 of Baiae, near Naples, as attested by the pillars of the temple of Jupiter Serapis, of which 

 a view is here given, sufficiently illustrated by a preceding description, is more explicable 

 in that region by the earthquakes of which it has been the focus, and by the gradual 



shrinking and expansion of the strata in periods of vol- 

 canic repose and activity. Some accurate experiments 

 made by Colonel Totten on the expansion of rocks by 

 | heat, show that a block of granite five feet long, by a 

 J change of temperature of 96 Fahrenheit, expanded 

 < 0-027792 inch, crystalline marble 0-03264 inch, and sand- 

 stone 0-054914 inch. The temple of Serapis, built of 

 course originally above high- water mark, sunk down a 

 considerable depth below the level of the sea, was again 

 re-elevated by the terrible events of September 1538, and 

 is now gradually subsiding the latter, probably, an effect 

 due to the shrinking of the strata by the radiation of heat. 

 Mr. Smith, in March, 1819, found its floor elevated about 

 six inches above the level of the sea; but, in May, 1845, 

 he found it covered to the depth of 18 inches at low 

 water j and 28 at high tide, the sea being perfectly calm 

 at the time. The custode of the building informed him 



change was progressive, amounting to about 1J English inch per annum; -and 

 that m thirty years he knew of a difference of at least 3 feet 6 inches in the height of the 



