chap. ix. Elevation of the Coast of Peru. 265 



me it appears far more probable that the movement 

 was gradual, with small starts as during the earth- 

 quakes of 1822 and 1835, by which whole beds of shells 

 attached to the rocks were lifted above the subsequent 

 reach of the waves. M. d'Orbigny also found rolled 

 pebbles, extending up the mountain to a height of at 

 least 600 feet. At Iquique (lat. 20° 12' S.), in a great 

 accumulation of sand, at a height estimated between 150 

 and 200 feet, I observed many large sea-shells which I 

 thought could not have been blown up by the wind to 

 that height. Mr. J. H. Blake has lately 1 described 

 these shells : he states that ' inland toward the moun- 

 tains they form a compact uniform bed, scarcely a trace 

 of the original shells being discernible ; but as we 

 approach the shore, the forms become gradually more 

 distinct till we meet with the living shells on the coast.' 

 This interesting observation, showing by the gradual 

 decay of the shells how slowly and gradually the coast 

 must have been uplifted, we shall presently see fully 

 confirmed at Lima. At Arica (lat. 18° 28'), M. 

 d'Orbigny 2 found a great rauge of sand-dunes, four- 

 teen leagues in length, stretching towards Tacna, in- 

 cluding recent shells and bones of Cetacea, and reach- 

 ing up to a height of 300 feet above the sea. Lieut. 

 Freyer has given some more precise facts : he states 3 

 that the Morro of Arica is about 400 feet high ; it is 

 worn into obscure terraces, on the bare rock of which 

 he found Balini and Milleporse adhering. At the 



at a depth of 300 feet, and at a depth of 600 feet several of these 

 same shells were accumulating in great numbers in horizontal beds. 

 From what I have myself seen in dredging, I believe this to be 

 improbable in the highest degree, if not impossible ; and I think 

 every one who has read Prof. E. Forbes's excellent researches on the 

 subject, will without hesitation agree in this conclusion. 



1 Silliman's ' Amer. Jour, of Science,' vol. xliv. p. 2. 



2 'Voyage,' &c. p. 101. 



8 In a letter to Mr. Lyell, 'Geolog. Proc' vol. ii. p. 170. 



