196 GEOLOGY AND CLIMATE. [1839 



vesicles. The rocks of basaltic lava contain augite, olivine, 

 common feldspar and albite. All the higher hills and moun- 

 tain peaks are crateriform. The beaches consist of a light- 

 colored sand, composed of a mixture of coral and shells. 

 Coral debris is found on the smaller islands, and along the 

 shores of the larger ones. The soil is principally formed of 

 decomposed volcanic rocks and vegetable mould. 



The climate is mild and agreeable, and the mean temper- 

 ature about 80°. It is more moist than at Tahiti, and the 

 vegetation is more thrifty. Nearly one third of the days in a 

 year are rainy. From April to November, the season is fine, 

 — the winds being light, and affording merely a pleasant 

 variety to the long-continued calms. During the remainder 

 of the year high winds prevail, principally from the south- 

 ward and eastward. Destructive hurricanes sometimes 

 occur, and earthquakes are not infrequent. The latter are 

 not usually violent, but produce a slight wavy motion, like 

 that of a vessel in an ordinary sea. 



(3.) On the northwest side of Manua, there is a small 

 settlement, and anchorage ground for vessels of light draught, 

 with a pretty little cove to land in, in pleasant weather. 

 Near the village are a number of irregularly-shaped stone 

 walls, the object of the erection of which is not known, but 

 they are supposed to have been intended for defence. 



Pago-pago, on the south side of the island of Tutuila, is 

 the largest, and in many respects the most important harbor, 

 in the group. It is deep and land-locked — penetrating so far 

 into the interior as to cut the island nearly in two, and lined 

 on both sides by steep inaccessible precipices, from eight 

 hundred to a thousand feet high. The coast, on either hand 

 of the entrance, which is about one third of a mile in width, 

 is bold and rugged. Opposite the opening, at some three 

 miles distance from the shore, is a coral bank on which the 

 sea breaks in stormy weal her. Except during a strong 

 southerly gale, vessels of almost any class may run into the 

 harbor in safety. If the wind be unfavorable, it requires con- 

 siderable tacking to get in or out, but the place boasts a white 



