278 



DISTRIBUTION OF PLANTS. 



exceeding four thousand feet in elevation, is almost constantly con- 

 cealed in the clouds; and only once during our prolonged stay became 

 visible. The superior elevation would not at first be suspected ; the 

 land rising all around in an exceedingly gentle regular slope, its even- 

 ness interrupted only by occasional knob-like hillocks. On landing, 

 the peculiar topographical features were explained ; the island being 

 covered with lava-streams, that had flowed downwards and outwards 

 from the central summit ; there were no ridges, nor ravines ; nor even 

 streams of running water ; the profuse rains sinking into the porous 

 lava, to reappear in copious springs all around the island, just above 

 the tide. In all my excursions during nine days on shore, cellular 

 lava was the only kind of rock met with : but towards the North point 

 of the island, I visited a more recent lava-stream, wide-spreading, 

 known to the natives as the " Mu," and distinguishable by the more 

 flattened surface and more distinct concentric folds left in the rock in 

 cooling. This lava-stream proved old enough to be overgrown with 

 large trees ; and there did not appear to be any tradition of its erup- 

 tion ; but earthqualces were spoken of, as not rare. 



On the 24th, Capt. Ringgold, in the Porpoise, completed the circum- 

 navigation of the island; and in the evening, I returned on board. 



On the 25th, the Porpoise left Savaii, returning Eastward. We 

 sailed near Apulima; and next, along the South side of Upolu; and 

 on the 29th, entered the harbor of Pango Pango in Tutuila. 



On the 9th of November, the Porpoise left Tutuila, sailing West- 

 ward ; and at sunrise on the 10th, arrived at Apia, where I rejoined 

 the Yincennes. Instead of again landing at Apia, I visited Mr, Rich 

 in the Peacock, and looked over his collections ; this being the last 

 day of our stay at the Samoan Islands. 



Climate. The climate proved to be the most rainy I ever expe- 

 rienced. The superior humidity is shown by the universal rankness 

 in the vegetable growth ; (and is impressed even on our prepared spe- 

 cimens ; which, though not all collected in the rain, can to this day 

 be identified by the discoloration). 



I kept no journal of the weather; but my memoranda contain 

 incidentally the following notices : 



Oct. 10th; approaching Tutuila; calm during the day, with rain. 



11th; in the Porpoise, off Tutuila; calm all the preceding night and most of this 



day, but some squalls with heavy rain. 

 l'2th ; approaching and off Upolu; mostly calm. 



