Volcano of Kirauea. 
33 
bounds and flowed down in confusion a distance of forty 
miles, have stood firm, and, like precious fragments of 
history, form an interesting subject of the traveller’s inves¬ 
tigations. 
The highest point of these ruins was determined, by 
repeated calculations, to be 5054 feet above the level of the 
sea. They resemble the outer edge of a cup, to which a 
portion of the overflowing matter adheres ; and show that 
the crater, just before its being emptied, was brim-full of 
molten lava. This vast accumulation of igneous matter 
was, however, the work of time : the ancient walls, which 
I quote as my authorities, show by layers of vegetable 
matter, which often overlie those of volcanic origin, that 
their construction proceeded at distant intervals, and was 
regulated by the gradual induration of the volcanic 
streams. During these intervals there must have been a 
variation in the intensity of the heat, and in the conco¬ 
mitant productions of Nature. Frequently a formation 
of blocks of lava, compact, fine-grained, and united, 
follows one of quantities of volcanic ashes and earthy 
substances, similar to tufa, or rather to Pepeira, which 
in its turn is succeeded by one of porous lava. One for¬ 
mation affects the magnet, the other not: in one case 
the porous cavities contain crystals of laminar or li g „i_ 
form talc ; in the other, augite, olivin, and shorl, through¬ 
out the whole length and thickness of the bed. It would 
even appear, judging from a specimen which I disco¬ 
vered in a cleft of the ancient crater, that the same bed 
must have been ejected, formed, and have again under¬ 
gone the action of other still more powerful fires by 
which its surface has been altered ; 80 that the interio’r of 
the formation displays argillaceous substances, petrosilex 
and crystals of hornblende, while the exterior, which 
has formed part of the wall of the crater, has become 
vitrified and cracked, displaying i n its crevices minerals 
VOL. TI. NO. VI. D 
