322 SAMOAN ISLANDS. 
partially cellular rock (var. 3), were seen scattered over the soil. The 
layers below were concealed by the soil. The layers of the same 
basaltic rock crop out two miles distint, and were found in scattered 
fragments on different parts of the ridge. The light scoria so abun- 
dant at Tafua does not occur here. All the appearances of the place 
are quite different from tliose of Tafua: the cone low and flat; the 
ascent very gradual; the edges of the crater broader; and the cavity 
not one-sixth as deep. Unlike Tafua, the mountain nearly, or quite 
to its summit, consists of solid lava. Cinders and scoria were there- 
fore but sparingly ejected at the last eruption of the crater. 
These accounts of the craters of the western district are necessarily 
imperfect, both on account of the small amount of time allotted for 
their examination, and because of the soil and vegetation that enve- 
lope the whole surface, scarcely leaving a single point exposed. We 
might have much to say of the stratification, the alternation with 
tufa, displacement of dikes, &c., &c., but these facts are all concealed 
from view. ‘The general dip of the successive currents may be in- 
ferred from the slope of the mountain: this shows that the inclination 
is from three to six degrees. KEven the gorges, with nearly vertical 
sides, that cut deep into the sides of the mountain, are equally en- 
veloped with soil, and clothed in the same luxuriant vegetation. But 
along the shores the rocks are often visible, and present some facts 
worthy of remark. 
Many of the currents have the recent aspect of the most modern 
volcanic products. ‘Twisted scoria in scattered fragments mark their 
path over the face of the country, and the surface of the stream is 
drawn out in long ropy lines. This is so finely developed that even 
small hand specimens exhibit it perfectly; occasionally we may 
break off irregular cylindrical masses, not two inches in diameter, 
which appear as if drawn out and twisted by art. These evidences 
of subaerial volcanic action may be seen at Sangana, where the surface 
is in some parts thickly strewed with fragments of scoriaceous lava. 
At Apia, near the waterfall, in the stream, similar though less striking 
facts may be seen. Just above the fall, the stream is crossed obliquely 
by raised lines of rock, a foot high, running nearly parallel with the 
edge of the fall. They appear like the successive ridges that are 
common on the surface of recent lava streams, produced by the inter- 
rupted progress of the slow-moving lava. The rock is a black ferra- 
ginous basaltic lava, and has a very rugged exterior. It is like the 
recent lavas of Oahu and Kauai. 
