200 I. Bowman — Physiography of the Centred Andes. 



The most extraordinary development of wave-cut terraces 

 observed were those at the port of Mollendo, in southern 

 Peru, fig. 3. The terraces increase in height from the northern 

 part of the Peruvian coast and reach a splendid development 

 at this point. They are visible at sea as great, long, gently- 

 sloping, rock benches of huge size. Opportunity was afforded 

 for the more detailed examination of their upper surfaces than 

 was possible in the preceding cases (Payta, Lomas, Pisco, Eten, 

 etc.), and it was found that evidence for their formation by the 

 sea and subsequent uplift to a height of at least 1,500 feet is 

 conclusive. At an elevation of 800 feet, a clay bank was 

 observed in the side of a gorge, or quebrada, in which in a 

 natural position were found recent shells of the same sort as 

 those now found in the present beach. It appears that, after 

 the formation of the terrace at this level and its partial dissec- 

 tion as the result of elevation, it was again submerged long 

 enough and deep enough for the formation of the clay and 

 the deposition of the shells. A second uplift then brought 

 the whole above water and it is this movement that is continu- 

 ing to-day. About the inner margin of the terraces are coves 

 like those now seen at many places on the present strand-line 

 or but a little above it. They are not so clearly distinguish- 

 able as the latter because of the partial filling or obliteration 

 that they have suffered, but their characteristic outlines are 

 still to be made out with certainty. The whole aspect of the 

 terraces with their regular outlines is in striking contrast to 

 the highly irregular forms of the mountain side above them 

 where the planing action of the sea is not expressed. 



It would be a repetition of the foregoing descriptions to 

 note the individual features of the different terraces observed 

 along the coast farther south ; and these have been described 

 to some extent in the accompanying list of papers,* and their 

 description here is unnecessary. At Iquique, at Tocopilla, Anto- 

 fagasta, and elsewhere, they are developed as clearly as in the 

 preceding cases. In each case the topographic outlines are as 

 clear an index of their manner of formation as are the shells 

 found upon the terraces at Payta and Mollendo. Though these 

 shells are interesting confirmatory evidence, they are not really 

 essential to the proof of formation by the sea and recent up- 

 lift, for the topographic evidence is of a thoroughly conclusive 

 sort. 



* The literature of the subject is still very limited. The following are a 

 few of the more important references : 



a. Francisco Vidal Gormaz, Depressions and elevations of the southern 

 archipelagoes of Chile (Scottish Geograph. Mag., Jan., 1902). 



b. Von Otto Nordenskjold. Ueber einige Erzlagerstatten der Atacama- 

 wiiste (11 B. Geol. 1. Univ. Upsala, iv, 1898). 



c. D. H. Evans, Notes on the Raised Beaches of Taltal (Quart. Jour. 

 Geol. Soc, xliii, 1907). 



d. Charles Darwin, A Naturalist's Voyage, etc. Ed. of 1860. 



