line, one about 200 feet inland on the 
most central ridge at the height of 20V 
feet, the other across the large cove on 
the brow of the cliff, 126 feet high. 
The latter station was upon a ruined 
terrace of stones, probably one of 
several house foundations which the 
very accurate Dr. Baldwin- informs 
me that Kamehameha III found on 
Nihoa, being not far from the best 
landing and the chief water hole. An 
accurate telemeter measurement gave 
the horizontal length of my base at 
1,168 feet, from which all my heights 
and distances are derived. I judge 
the possible error not to exceed six 
feet, or .005. A magnetic azimuth 
was employed, circumstances pre¬ 
venting solar observations for true 
azimuth. The two stations differed 
four degrees as to the direction of 
the needle. The azimuth of the first 
station was adopted, being judged 
least subject to local attraction. 
A quite full survey of the coves was 
secured by means of depression angles 
to the water's edge, verified by a few 
intersections. Several of the most 
prominent peaks overhanging the 
outer shore were also well located by 
intersections, and heights deter¬ 
mined. A large number of careful 
sketches, together withJVfr. Williams' 
excellent photograph, supply ample 
means for filling out the outer coast 
lines and the contours. An outline 
of the island, drawn by Mr. Rowell, 
from the summits, is a most valuable 
aid. Mr. Rowell’s aneroid measure¬ 
ments are quite uniformly 60 or 70 
feet short of my triangulated heights. 
But this is fully accounted for by his 
acknowledged defective correction for 
sea level. 
We were xwoceeding to occupy a 
third station above the south point, 
making a second base, and expecting 
two hours more work whereby to elab¬ 
orate our survey, by the help of many 
flags set by Mr. Rowell on lofty points, 
when a fire broke out about 300 feet 
above my main station, and spread 
with great speed and force in the 
masses of dry tindery matter. This 
at once filled the island with such 
volumes of smoke that it became im¬ 
possible to pleasure an angle on any 
flag. The last of the hundreds of peo¬ 
ple who had landed had already all 
disappeared below the cliffs, and were 
slowly embarking. We reluctantly 
retired from our work, and followed 
them. Within an hour my station 
had been swept by the flames, which 
spread steadily in every direciion. 
The embarkation was much more 
difficult and hazardous than the land¬ 
ing, the sea having risen somewhat, 
as well as the tide. Two boats had 
been swamped, one of them causing 
the loss of most of the negatives taken 
on shore, and destruction of the 
cameras, Mr. Deverell saving his 
own life by extreme activity ami 
strength. We were so happy as to 
get our instruments aboard safely. I 
believe that no person suffered any 
serious injury, all but a few whites 
being at home in such rough work. 
The Princess was conspicuous for 
her adroit and agile spring through a 
dangerous surge upon her whale boat 
as it darted up to the rocks for an in¬ 
stant. 
. 
..ii-S Sgt wSsilM# >. 
The extreme length of Nihoa from 
W.N.W. to E.S.E. is not far from 5,- 
200 feet. Its average width about 2,000 
feet, giving an area of about 250 acres. 
Four-fifths of this is very steep, grassy 
slope, the rest precipices. I did not 
see enough level ground to build a 
native hut upon without terracing. 
The general contours are much like 
those of Punchbowl towards Waikiki, 
save that the ridges tend inward in¬ 
stead of radiating outward. 
The N.E. pinnacle, which over¬ 
hangs, is 869 feet high, with a possible 
error of 10 feet. The highest N.W. 
pinnacle is 900 feet, with possible 
error of 20. Had a third station been 
occupied, the element of error would 
have been minimized. I trust shortly 
to submit to you a finished map of 
the island. 
In respect to the geology of Nihoa, 
I regard the evidence as complete and 
conclusive, that it is the small re¬ 
maining portion of an extremely 
eroded and deeply submerged volcanic* 
dome homologous with the larger 
islands of the Hawaiian group which 
still survive in their various stages 
of present upbuilding, recent extinc¬ 
tion of volcanic activity, less or more 
advanced erosion, and slighter or 
deeper subsidence. I would not place 
undue stress on the very obvious fact 
of progressive extinction from N.M. 
to S.E., nor of progressive increase of 
atmospheric erosion from >S.E. to 
N.W., nor of apparently deeper sub¬ 
sidence progressing in the same di¬ 
rection , nor of Nihoa bei ng equidistant 
with the other main volcanic centers 
of the chain, all which would lead 
us to look to the site of Isihoa foi a 
volcanic center still more ancient 
<than Kauai. 
For positive evidence we must take 
the form and structure of the island 
itself. In the first place, the sub¬ 
stance of the island is homogeneous 
with the substance composing the 
central interior portions of Oahu and 
Maui, as seen in their inner ridges 
and pinnacles where the deepest ero¬ 
sions have most thoroughly eaten 
down to the hearts of their ancient 
domes. I have uniformiiy found 
those interior formations not basaltic, 
but scoriaceous. It appears that dur¬ 
ing the period of upbuilding, clink- 
erv and scoriaceous ejecta pile up at- 
the center of the volcanic dome and 
form its core, while the outflowing 
streams cf lava build up its circum¬ 
ference in layers of more or less ba¬ 
saltic formation. Nihoa seems to be 
a pair of clinkery pinnacles out of the 
inner core of a once mighty dome 
which has been eaten down by winds 
and rains for thousands of feet, and 
during unreckoned ages. 
But the conclusive evidence in my 
view is the presence of the numer¬ 
ous parallel basaltic dikes, which, as 
stated above, cut the island from 
end to end and from summit to base. 
Such dikes can only be produced by 
lava during an eruption, rising and 
filling thin fissures such as an earthi- 
quake might produce across the mass 
of the dome. Possibly each dike may 
be the work of a separate eruption of 
the volcano. At an\> rate a great 
period must have elapsed between 
the slow piling up of the successive 
