ANNIVERSARY ADDRESS OF THE PRESIDENT. 193 



to this most important class of geological phsenomena ; changes 

 which may almost be said to come within the range of our expe- 

 rience, and which appear to afford a key to the right solution 

 of many analogous changes during periods long antecedent. We 

 have for some time known that eroded rocks, and long lines of level 

 beds or terraces of shingle, sand and clay, mixed with broken shells 

 like what we now find at the sea-shore, are met with along the coasts 

 of Sweden, and in Norway and the islands adjacent, from the Naze 

 to the North Cape, and even to Spitzbergen. These beds of detritus, 

 which have been found at elevations of 600 feet, and are sometimes 

 above 160 feet in thickness, usually rest on the solid rock, and 

 frequently contain shells in a perfect state of preservation as to 

 freshness and colour, the bivalves, which are identical with species 

 now living near the shore of the adjoining sea, retaining their uniting 

 ligament ; indicating that the changes have occurred, either during 

 the latter part of the tertiary period, or at the commencement of the 

 existing geological period. These facts are described in the writings 

 of Playfair, Von Buch, Keilhau, Sefstrom, Lyell and others, and 

 some very remarkable cases have recently been given in a memoir 

 by M. Bravais*, who resided a year in Finmark, between the seven- 

 tieth and seventy-first degrees of latitude, and who has measured 

 with great care a series of terraces or raised beaches in the Alten 

 Fiord, which extend over a line of coast from fifty to sixty miles. 



The western coast of our own island has also, as you know, afforded 

 some most remarkable instances of these changes of relative level of 

 sea and land, from the north of Scotland to Cornwall, and in some 

 cases at a much greater elevation than in Norway, as at Moel Try- 

 fane in Caernarvonshire, more than 1000 feet above the sea. That 

 they have not been found in as continuous extent in Britain as in 

 Norway is perhaps owing to this, that the shores of our island being 

 cultivated, these banks of loose materials would gradually become 

 obliterated. 



But it is not the shores of Europe alone that have afforded proofs 

 of these changes ; the continents of North and South America exhibit 

 them on a far grander scale, both on the Atlantic and Pacific coasts. 

 We are indebted to Mr. Darwin for descriptions of many remark- 

 able instances ; and some of these which have recently come again 

 under our notice, in the second edition of his 'Journal,' published 

 within the last few months, I will draw your attention to : I know 

 no geologist whose observations, and the inferences he draws from 

 them, are more to be relied upon ; for he examined the country he 

 describes evidently uninfluenced by any preconceived opinions. 

 They have besides a bearing upon some fresh accessions to our 

 knowledge of facts of this description, both in Europe and North 

 America, during the past year. 



At Coquimbo, in northern Chile, five narrow, gently sloping, 

 fringe-like terraces rise one behind the other, and, where best deve- 

 loped, are formed of shingle. At Guasco, farther north, the terraces 



* A translation of this valuable memoir is given in the fourth number of the 

 Quarterly Journal of the Geological Society. 



VOL. II PART I. O 



