128 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
tion of man’s occupation of the area for a few centuries perhaps in 
the past. 
Pissis (1875, p. 78-81) has described the distribution of the most 
recent marine elevated deposits of Chile. Beginning on the north 
in the plain which extends from the Bay of Antofogasta to that of 
POS Joe 
ose OS... 
oe ree ee eae rid 
MMAR EN ic 8 EW a 
PRR DL a ceaaian:  RE aede a e 
/33 —_] —— qt 
caldera |i Coquimbe— [st 2 
ie a a A a 
32 | cttta. Be =~ ~~», Concepcion [* —— 40 
RRS HRT PERE Bee Te P 
Miles. 0 199 200. 200 400 +500 600 700 800 809 1000 }100 1200 
Fic. 35.— Rise to the north of the Recent uplifted marine deposits of Chile, 
according to the data of Pissis (1875, p. 78-81). The dotted line shows 
apparent warped surface from Caldera southward. The line a—b gives 
the mean tilt-rate from Mejillones southward. The line c—d is drawn at 
the same tilt-rate to touch the elevated rock bench at Corral. 
Mejillones this plain, having there an altitude of forty meters, is 
represented by correlated deposits at constantly lower levels on the 
south as far as the 38th parallel. In the vicinity of Caldera the 
deposits rise from twenty-five to thirty meters above sea-level. 
About Valparaiso and San Antonio the level is maintained between 
fifteen and twenty meters. The city. of Concepcion is built on the 
sands at the mouth of the Rio Bio Bio and finally at Levau the de- 
posits risé scarcely two to three meters above the sands of the beach. 
Taking these data as given by Pissis and plotting the upper limit 
between Mejillones and Levau, the tilt-rate is shown by the graphical 
construction in Fig. 35. According to these observations made by 
Pissis as early as 1875 the coast from a point north of Valdivia shows 
a rise at the rate of about 0.13 ft. per mile for about 1,100 English 
statute miles. 
Valdivia and Corral lying to the south of this group of raised 
deposits as noted above shows evidence of depression preceding the 
last slight rise of the coast. Accepting Pissis’s altitudes for the height 
of the uplifted plain and assuming the above rate of tilting, the 
abandoned sea-caves south of Corral fall on a tilted plane about three 
meters above that of the formation of sands and shells, and may 
tentatively be regarded as at the sea-level under which the sands were 
laid down. 
