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complex. In the first place, the older sedimentaries were profoundly 
folded and probably also much faulted; in the second, erosion set in and 
truncated many of these folded beds; in the third, subsidence occurred 
and a coralline mantle was laid down upon these truncated folds, and in 
the fourth, the whole region received a thrust from below in which eleva- 
tion took place, but it was an unequal elevation, with tilting east, west, 
north, and south. The north and south tilt, which, however, may be 
decidedly more recent than the east and west one, is best seen in the 
vicinity of Argao, where the marine terraces incline to the north at 
an angle of about five degrees. 
Mr. Becker? has remarked upon the even sky line of the central part 
of the island and explains this as resulting from the peculiar growth of 
coral reefs, which grow up to a limiting plane, the surface of the water. 
This is undoubtedly correct, and the coralline mantle has suffered but 
little tilting in the region of the Cordillera. In the lower regions the 
even sky line is still well preserved in many places, but the tilting is 
marked. 
Since my return from the field, Mr. Bailey Willis’s brief discussion of 
his physiographic studies in Europe, appearing in the Carnegie Year- 
book,’ has suggested to me possible explanations for some of these 
phenomena, for which a ready solution did not seem to be at hand, and 
the Carpathian type of mountains, with their peculiar physiography, 
namely, folded Neocene strata subsequently tilted and warped with 
sink holes, seems to find an analogy in Cebu. 
Mr. Willis also emphasizes the fact that the growth of mountains is 
distinct from the existence of mountains by virtue of their structure. 
I am inclined to think that those of Cebu have grown rather than that 
they are due to inherent structure, for were it not for the great subsequent 
erosion, one might start from the coast and climb toward the Cordillera 
without being aware of anything more than a moderate ascent, for it is 
the afterwork of the streams which has made Cebu appear to be moun- 
tainous. The photograph on Plate IT shows what this work has been ; 
indeed, the similarity of this region to the Benguet country of northern 
Luzon is quite marked, although in reality its elevation is from 2,000 to 
3,000 feet less. 
Extended sections are rare, but one in Butuanon Creek was photo- 
graphed, showing the local warping in the Plocene limestone. We 
believe this phenomenon to be quite widespread over Cebu. (PI. IIT.) 
7 Becker, G. F.: Geology of the Philippine Islands, U. 8. @. 8. 21st An. Rep. 
(1902), 561. 
® Bailey Willis: Fourth Year Book, Carnegie Inst. (1905), 196. 
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