Xlviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



In my address last year I referred to the instances given by Mr. 

 Darwin of an elevation of the land on the western coast of South Ame- 

 rica. Those referred to had occurred after the creation of species of 

 mollusca now living in that region, but they do not afford any evidence 

 of belonging to the recent period, but must be referred to the pleisto- 

 cene epoch, and as such I shall have occasion to speak of them in an 

 after-part of the present Address. In the work recently published by 

 Mr. Darwin, he gives a detailed description of several instances of ele- 

 vations that have taken place in recent times, presenting the same 

 characters as those of earlier date ; and expresses his opinion that this 

 movement of the land, although subject to intervals of rest, is now, as it 

 has been at all former periods of geological time, one of the main causes 

 of the revolutions to which the surface of the earth is unceasingly sub- 

 ject. " The time, I believe, will come," he says, "when geologists will 

 consider it as improbable that the land should have retained the same 

 level during a whole geological period, as that the atmosphere should 

 have remained absolutely calm during an entire season* ." 



The island of San Lorenzo near Lima is upwards of 1 000 feet high, 

 and in one part of it there is a ledge of rock, containing an accumula- 

 tion of recent shells two feet in thickness, and above a mile in length ; 

 the highest part of which is 85 feet above high-water mark, the shells 

 being in nearly the same proportional numbers with those on the exist- 

 ing beach. Several of the univalves have evidently lain long at the 

 bottom of the sea, for their insides were incrusted vv^ith balani and 

 serpulse. In the midst of these shells Mr. Darv^in found a piece of 

 woven rushes, and another of nearly decayed cotton string, undistin- 

 guishable from similar things found in the burial-grounds of the ancient 

 Peruvians. These discoveries, and the whole appearance of the bed of 

 shells, seemed to him to render it almost certain that they were accu- 

 mulated on a true beach, since upraised 85 feet, after the Indians inha- 

 bited Peru. The island of Lemus, in the Chonos Archipelago, was 

 suddenly elevated by an earthquake in 1839. An English resident 

 stated to him that a part of the island of Chiloe had been raised 

 four feet in four years, and that the change had been gradual. The 

 island of Mocha, 70 miles north of Valdivia,was uplifted two feet during 

 an earthquake in 1835. At Valparaiso, between the years 1614 and 

 1834, there had been a rise of the land of 19^ feet, of which between 10 

 and 1 1 appeared to have been subsequent to 1817. The elevation had 

 been by insensible degrees, with the exception of the year 1822, when 

 the great and celebrated earthquake of that year raised the land sud^ 

 denly three feet over a considerable extent, and a slow rise of the land 

 is considered by residents there to be now in progress. There is also 

 evidence of subsidence on parts of the coast for some distance south and 

 north of Callao. 



Few countries present on so great a scale the operations of atmo- 

 spheric agency in disintegrating and transporting the materials of the 

 land as Central Russia does. The inferior solid rocky structure of the 

 country, as we learn from the recent work of Sir R. Murchison, is seldom 



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