white, soft, earthy mesotypic mineral, which intumesced under the blowpipe
in a remarkable manner. As the upper surfaces in all the half-filled cells
are exactly parallel, it is evident that this substance has sunk to the
bottom of each cell from its weight. Sometimes, however, it entirely fills
the cells. Other cells are either quite filled, or lined, with small
crystals, apparently of chabasie; these crystals, also, frequently line the
upper half of the cells partly filled with the earthy mineral, as well as
the upper surface of this substance itself, in which case the two minerals
appear to blend into each other. I have never seen any other amygdaloid
with the cells half filled in the manner here described; and it is
difficult to imagine the causes which determined the earthy mineral to sink
from its gravity to the bottom of the cells, and the crystalline mineral to
adhere in a coating of equal thickness round the sides of the cells.
(MacCulloch, however, has described and given a plate of ("Geolog. Trans."
1st series volume 4 page 225) a trap rock, with cavities filled up
horizontally with quartz and chalcedony. The upper halves of these cavities
are often filled by layers, which follow each irregularity of the surface,
and by little depending stalactites of the same siliceous substances.)

The basic strata on the sides of the valley are gently inclined seaward,
and I nowhere observed any sign of disturbance; the strata are separated
from each other by thick, compact beds of conglomerate, in which the
fragments are large, some being rounded, but most angular. From the
character of these beds, from the compact and crystalline condition of most
of the lavas, and from the nature of the infiltrated minerals, I was led to
conjecture that they had originally flowed beneath the sea. This conclusion
agrees with the fact that the Rev. W. Ellis found marine remains at a
considerable height, which he believes were interstratified with volcanic
matter; as is likewise described to be the case by Messrs. Tyerman and
Bennett at Huaheine, an island in this same archipelago. Mr. Stutchbury