42 EXPEDITION OF THE "ALBATROSS," 1899-1900. 



we know to have been active over very extensive areas of the Pacific 

 from Tertiary times to the present day. Yet in some of the Pacific archi- 

 pehigos the areas upon whicli the Tertiary limestones were deposited must 

 have been of considerable extent, as for instance tlie plateau of the north- 

 western Paumotus, the plateau of the Tonga Islands, and the plateau 

 upon which the eastern islands of the Fiji Archipelago rise : the so-called 

 Lau or Windward group of Fiji. Conditions similar to those under which 

 the central Pacific Tertiary limestones were deposited must have been of 

 wide geographical range; they appear, in addition, in the Pliilippines, 

 in the Loyalty, the New Hebrides, and Solomon Islands, in New Caledonia, 

 in the China Sea, at Christmas Island, in the Indian Ocean, in the Red Sea, 

 and in the West Indian area. 



We left Guam in time to reach Rota by day, and found that this island 

 also is a mass of elevated coralliferous limestone, the highest cliffs of which 

 reach a height of 800 feet. Perhaps in none of the elevated islands have 

 we been able to observe the terraces of submarine elevation as well as at 

 Rota, especiall}' in the small knob at the southwest point of the peninsula 

 separating Sosanlagh and Sosanjaya bays, which itself is also terraced ; no 

 less than seven distinct terraces could be traced. There was no sign of 

 any volcanic outburst except at the northwest point of the island, where 

 both the character of the slope and of the vegetation would seem to 

 indicate a volcanic structure. 



It is quite probable that others of the Ladrones, like Saipan and the 

 islands to the south, are composed in part at least of elevated limestone, 

 judging from the hydrographic charts and the sketches which accompany 

 them.* On many of the northern Ladrones there are active volcanoes, so 

 that it is very possible that the volcanic outbursts which have pushed 

 through the limestones, or have elevated parts of the islands of the group, 

 are of comparatively recent date. 



During the last part of our cruise, from Suva to Guam, the unfavorable 

 weather greatly interfered witii our deep-sea and pelagic work ; in fact, 

 with the exception of the soundings made to develop as far as practicable 

 the depths in the regions of the various coral-reef groups we visited, we 



1 II. O. Chart No. 1718. 



