KOTA. 377 



after examining the charts of the Lach'ones to find that Rota, as well as 

 Guam, consisted of elevated coralliferous limestone. The western extremity 

 of Rota is formed by a long rectangular peninsula ; its terraces are most 

 distinctly marked and five periods of elevation are clearly to be distin- 

 guislied (PI. 199, fig. 2). The western peninsula is connected by a narrow 

 neck with the main island (PI. 233, fig. 5), a huge ma.ss of coralliferous 

 limestone sloping equally in all directions, but most distinctly terraced 

 (PI. 199). In So.sanjaya Bay and off the northwestern shore of Rota the 

 island is flanked by a narrow reef flat (Pi. 233, fig. 5). The outliers and 

 horse-heads on the Avestern shore (PI. 233, fig. 5) indicate the amount of 

 erosion to which this island has been subjected. 



On Rota the terraces markiuij the successive elevations of the .southern 

 Ladrones are adtnirabl}' preserved. At a distance of three miles off shore 

 five terraces could be distinguished. The summit of the island is almost 

 level (Pis. 199, fig. 2; 233, fig. 5). Coming from the south we could see 

 no indication of any volcanic outbursts. The spit forming the southwestern 

 extremity of Rota, separating Sosanlagh and Sosanjaya Bays, also shows 

 remarkably well-defined terraces (PI. 199, figs. 1, 2). There are four of 

 these on the southernmost spit, and, when facing the main island, at least 

 seven terraces are pin inly indicated. The face of the southern spit is riddled 

 with caves (PI. 199. fig. 2). The lower terrace is deeply undercut, showing 

 traces of two stages of elevation, one not more than three or four feet, 

 identical in height with the low terrace de.scribed at Cabras Island. Look- 

 ing across the low land separatmg the southern promontory of Rota from 

 the main island, we could see numerous caverns in the vertical face of the 

 cliffs of the main mass of Rota. As we steamed north we observed that 

 the slope of the northwestern point, as well as the character of the vege- 

 tation, indicated a volcanic outburst at that exti'emity of the island (Pis. 199, 

 fig. 1 ; 233, fig. 5). 



It is probable that others of the southern islands of the Ladrones we did 

 not examine are, like Rota and Guam, elevated coralliferous masses forming 

 the summit of an extensive limestone plateau thi'ougli which more recent 

 volcanic rocks have burst at different points. After volcanic outbursts the 

 elevated coralliferous limestone beds have often been denuded and eroded 



