356 "ALBATROSS" TROPICAL PACIFIC EXPEDITION. 



sliore, so that inland one finds stagnant pools of water, in which a 

 dense growth of mangroves flourishes (PI. 192, fig. 1). A sluggish stream 

 of brackish water winds through the flat between Mount Ton Azan and 

 the main range. This stream appears on the western side of the island, 

 about one and one-half miles north of Mission Station. It has numerous 

 small tributaries and is from three to three and one-half feet deep and 

 about twelve feet wide; its channel is scoured by the tide, as well as 

 by the fresh water flowing from the hills. The edge of this stream 

 is covered with black volcanic mud containing coral fragments and coral 

 sand ; a dense wall of mangrove bushes follows its course. Neither beach 

 rock nor coral reef rock was found in place or on any part of the shore 

 flat to the south of the village ; but here and there one finds small loose 

 blocks of eroded coral. These extend inland to the foot of the mountain 

 slope ; they are nowhere more than five feet above high-water mark. 

 Several small islands of beach rock conglomerate lie oft' the beach line 

 of the western coast of Uola ; they are raised only about eight inches 

 .above high-water mark and support a fine growth of mangroves (PI. 192, 

 fig. 1). They are probably covered by high spring tides; there is little 

 evidence to show that they are elevated reef rock. 



Ruk, the next island in size in the eastern half of the lagoon, is 

 four miles in length, with a greatest width of about one and one-fourth 

 miles (PI. 193, fig. 1). 



Toloas Island is irregularly circular, about two miles in diameter (PI. 193, 

 fig. 1), with a long spur extending off the eastern coast nearly a mile, and 

 parallel to it a low volcanic ridge, forming the island of Erin ; Toloas and 

 Erin are included within the same fringing reef flat. 



To the south of Toloas rise a couple of low volcanic islands. To the 

 soutiieast of Ruk lies Umol (PI. 193, fig. 1); it is irregularly triangular in 

 shape, a little over two miles long, with an extensive spit running south 

 similar to that of Toloas. At the base of the spit the low island of 

 Atokin has been thrown up ; it indicates the position of a former ridge 

 like that of Kutua Point on Toloas. Between these four larger islands 

 and the barrier reef flat, distant from five to eight miles, extends a line 

 of low volcanic islets : Herit, Fanamu, Onna, Onnaram, Fananan, and 



