GEOLOGY OF PERU—ADAMS. 491 
RAISED BEACHES. 
The action of the sea in cutting cliffs may be well observed along 
the coast of the northern coastal plains, where the Tertiary forma- 
tions at many places rise in sheer bluffs. The same process has been 
in operation at other places on the coast where elevation has taken 
place and the cutting action of the sea is displayed in a succession of 
marine terraces. These are especially noticeable on the coast between 
Pisco and Lomas, where the Pisco formation displays approximately 
ten distinct terraces rising to a height of perhaps 1,000 feet. Along 
Top of Aill on North side of Ocofia Fiver af its mouth 
B/S0 Fz. 
Terrace cut in igneous rock 
2500 %¢. 
Terrace covered with river bow/dera 
- 480078. 
4300 £2. 
Yellow clay ond sandstore 
with some bhousders 
Fig. 10.—Section showing marine cut terraces at the mouth of the Ocona River. 
the southern part of the Peruvian coast in front of the range of coast 
hills where the rivers have cut their canyons through, there are ter- 
races in the igneous rocks which constitute the hills and also in the 
remnants of what were once delta formations of these streams. ‘The 
terraces at the mouth of the Ocofa River, as seen by the writer and 
measured with an aneroid, are represented in the following sketch 
(fig. 10). The upper terrace at Ocofia is the highest one which was 
found on the coast. 
Terrace cut in igneous roch 
10507. 
Sloping terrace 
TSOFE. 
Fic. 11.—Section showing marine cut terraces at the mouth of the Ilo River. (Compare 
fig. 8.) 
The railroad station, Tambo near Mollendo, on the Southern Rail- 
way, has an elevation of 1,000 feet and is situated on the north side of 
the River Tambo near its mouth, on an extensive terrace which must 
have attracted the attention of many travelers, although its origin is 
not explained in any scientific article which has come to the writer’s 
notice. 
The terraces south of the Ilo River, near its mouth, are indicated in 
the above sketch (fig. 11). 
