J. D. Dana—History of the Changes in Kilauea. 451 
The observations here reported were made in December, 
1840, the party leaving on the 18th for the top of Mt. Loa. 
Other observations on Kilauea were made by Capt. Wilkes and 
his officers just a month later, in January ; and these include 
a topographic survey of the crater by Capt. Wilkes, who says: 
‘“‘T measured my base and visited all the stations around the 
crater in their turn.” On page 175 it is stated that the obser- 
vations of one of the officers of the expedition, Lieut. Budd, 
made the depth to the black ledge 650 feet, and thence to the 
bottom 342 feet, whence “the total depth 992 feet.” On page 
179, we learn that Lieut. Eld was instructed to make the meas- 
urement of the depth, ‘“‘as I was desirous of proving my own as 
well as Lieut. Budd’s observations ;” and then follows the 
remark, ‘‘The measurements coincided within a few feet of each 
other.” Had the precise numbers obtained by Lieut. Eld been 
reported we might be able to remove the doubts left by the 
varying statements. But the fact that Lieut. Budd’s results are 
inserted by Capt. Wilkes on his own map of the crater is a 
strong reason for believing that the coincidence was between 
the results obtained by the two Lieutenants. 
I add here a few words from my own report, on the surface 
about Kilauea, on the stratification and rock of the walls and 
the absence from them of scoria, and on the escaping vapors of 
the Great Lake. “The country around [Kilauea] is slightly 
raised above the general level, as if by former eruptions over 
the surface.” The walls ‘consist of naked rock in successive 
layers” ‘‘and look in the distance like cliffs of stratified 
limestone.” The rock is a heavy compact dark gray to gray- 
ish black lava [basalt] containing usually fine grains of chryso- 
lite; and no layers of scoria like that making a crust of 
two to four inches over the solidified lavas from the lava-lakes, 
intervene even in the walls of the lower pit, each new stream 
having apparently melted the scoria-crust of the layer it flowed 
over. While the cooled Java-streams over the bottom were of 
the smooth-surfaced kind [and would be called pahoehoe] there 
was the important distinction into streams having the scoria- 
crust just mentioned, and those having a solid exterior and no 
separable crust, pointing to some marked difference in condi- 
tions of origin. ‘The vapors rising from the surface of the 
Great Lake were quite invisible until reaching an elevation 
where part became condensed by heat” (p. 179); here began “a 
column of wreaths and curling heaps” and upon this column, 
‘the broad canopy of clouds above the pit seemed to rest”’ 
(p. 172). 
[To be continued. | 
