214 Captain Hall's details of experiments 
of a point of land running into the sea at the south end of Abing- 
don Island, where it forms the western side of a small bay, 
about a mile across. The point is part of an ancient stream of 
lava which has flowed down the side of a peaked mountain in 
the middle of this end of the island. The summit of this peak 
is between two and three miles from the station, in a direction 
nearly north, and is about two thousand feet high : it slopes 
rapidly at first, forming a tolerably steep cone, but terminated 
by a broad and gently sloping base of a mile and a half. The 
sides of the mountain are studded with craters, or mouths, from 
whence at different periods streams of lava have issued, and 
running down to the sea, have there formed projecting points, 
such as that on which we fixed our station. The western 
face of the island presents a cliff nearly perpendicular, and 
not less than a thousand feet high ; it exhibits the rude 
stratification of lava, tuffa, and ashes, which characterizes 
the fracture of ancient volcanic mountains. I am thus mi- 
nute in describing this island, that you may be enabled to 
judge how far its density may have modified the results of 
the experiments. It is ten or twelve miles long ; the north 
end being a continued system of long, low, and very rugged 
streams of lava ; the peak standing about one-third of the 
whole length from the southern extreme, where our station 
was. The rock at different places not far from the station 
was found to be full of caves, into which the tide flowed and 
ebbed through subterranean channels ; the outer crust of the 
stream having, as usual, served as a pipe to conduct the lava 
off: it is therefore probable that our foundation may not 
have been the solid rock, a circumstance which, taken along 
with the general hollow nature of volcanic districts, and the 
deepness of the surrounding ocean, renders these experiments 
