12 



CALIFORISfIA ACADEMY OF SCIEN'CES. [PROC. 3D Ser. 



tended along the cliffs bordering the island,^ but it has been 

 since removed by a prolonged period of active cliff erosion. 

 That the evidence is preserved here is due to the fact that 

 the terracing extended so far inland. This belongs to an 

 earlier period than the terraces of the main coast and of San 

 Clemente. 



The other terraced structure occurs in the canon back of 



Figure 4 — Dissected alluvial fan, southeast side of Avalon Canon. 



Avalon (see fig. 4) , about half a mile from the shore-line, and 

 is seen on both sides of the canon — which is about a quarter 

 of a mile wide at this point — as a broad platform extending 

 up some distance into the canon-like opening on either side 

 of the main valley. Its front edge has a gentle seaward 

 slope, while from front to rear it rises graduall}* toward the 

 hills. A sharp ascent of about forty or fifty feet marks the 



1 Rolled pebbles were found scattered over a small area near the southeastern end 

 of the island, at an altitude of 1,000 feet; also on the main ridge south of Avalon Canon, 

 at about 1,400 feet; but the remains of an Indian camp within a hundred feet, in each 

 case, made the evidence doubtful. In neither case, however, were any pebbles found 

 among the remains marking the camp. 



