360 J. D. Dana — History of the Changes in Kilauea. 



ejected from the volcano, and numerous lava-bombs were picked 

 up. Ashes also cover the country to the south and southwest 

 over the Kau desert for several miles." 



But it is still not appreciated that Mr. Dibble's words "many 

 miles around" are true if made to include the whole circuit of 

 Kilauea, even the vicinity of the Volcano House, and that the 

 projection of stones preceded that of the light scoria ("pumice"), 

 as Mr. Dibble's account says ; yet was itself preceded by a 

 great shower of volcanic ashes or sand. The facts show, more- 

 over, that the stones are in great numbers and of large size to 

 the west and northwest of the crater. The deposit has its 

 maximum thickness over a large area south and southwest of 

 the crater, where it is twenty-five to thirty feet thick and ex- 

 tends ten miles or more away. It is well exposed to view 

 along the fissures. The lower twenty to twenty-five feet of the 

 deposit consist of yellowish brown beds of tufa, the material 

 very fine volcanic sand and hardly consolidated. Above the 

 tufa are two to three feet of a coarse conglomerate consisting 

 chiefly of stones ; and above this stratum, a bed twelve to six- 

 teen inches thick of closely packed brownish sponge-like scoria 

 ("pumice"), in pieces half an inch across to two or three inches. 



This sponge-like scoria contains the least possible amount of 

 solid matter, being about ninety-eight and one-third per cent 

 air, the rest glass ; for the small round cells have no walls ex- 

 cept a few slender threads, and it is about as light as a dry 

 sponge. On account of its lightness it is easily carried off by 

 winds as well as the sleepiest of waters, and hence the bed 

 is often left in patches. 



The ejected stones vary in size up to several cubic feet. 

 Those of one to two cubic feet are common, many are 20 to 30, 

 and one seen on the west side measured 100 cubic feet and must 

 have weighed over eight tons. Part are ordinary volcanic 

 scoria ; but the most of them consist of the more solid basalt 

 sparingly vesicular; and many of the larger are of a light- 

 gray kind very slightly vesicular or hardly at all so, only 

 slightly chrysolitic, and frequently having on the worn exterior 

 a faint banded appearance from alternating variations in com- 

 pactness of texture. Another kind varies in color from faintly 

 reddish to gray, is more or less vesicular, and contains a large 

 amount of chrysolite — suggesting the nature of a bomb, though 

 not having an exterior shell.* 



Groing from the southwest border northward and approach- 

 ing the highest point on the west side, the TJwekahuna station 

 of the survey, the deposit becomes thinner, but retains well its 



* The rocks collected on Hawaii have not yet arrived and hence only general 

 descriptions are here given. 



