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University of California. 



[Vol. i. 



The two highest terraces seem to be much older than those on 

 the southwest side of the island, from 1,320 feet down. Their sea- 

 cliffs are much more degraded, so that, although the terrace line is 

 a well-marked feature of the landscape when viewed from a distance, 

 the sharpness of the contrast between the cliff slope and the terrace 

 slope is not so apparent to the observer when he is on the immedi- 

 ate ground. There is, however, no reasonable doubt as to their 

 being sea terraces, as the beveled edges of the inclined strata of the 

 terrace floors and the horizontality of the rear amply testify to their 

 origin. Above the highest observed terrace, at 1,500 feet to the 

 summit of the island (1,964 feet), the topography has a non-terraced 

 aspect. This may possibly, of course, be due to the greater age of 

 the topography, terraces once existent having disappeared. 



The stream topography of the island is in harmony with the 

 character of the terraces. Streams are few, and it is very evident 

 that they have but begun their work of sculpture. On the upper 

 plateau of the island the drainage runs in open swails with shallow 

 trenches. In their descent over the great cliffs and terraces of the 

 southwest side of the island, however, the streams have cut sharp, 

 deep, steep-walled canons into the rocky floors. In the case of the 

 middle portions of the canons their abruptness and narrowness con- 

 stantly excite the surprise of the explorer. In walking along on 

 the rocky floor of a terrace, the trench will often scarcely be per- 

 ceived till the brink is reached, and its gloomy depths yawn verti- 

 cally beneath one's feet. Their narrowness and straightness give 

 them the effect of saw cuts across the terraces rather than of stream 

 courses. In their upper portions they are a little more open and 

 Y-shaped, while in their ' lower parts the streams have in many 

 cases made but very moderate incisions into the more recently 

 elevated terraces. In no case are the streams at base-level. Besides 

 these streams which descend from the upper plateau, trenching the 

 whole system of terraces, and therefore antecedent to the last thou- 

 sand ieet of uplift, there are numerous other minor water courses 

 which are consequent upon the uplift, having their sources in the 

 various ancient sea-cliffs. These have a much smaller share of the 

 rainfall to carry off, and their work is correspondingly less important; 

 but still they have in many cases made considerable headway in 



