MUSEUM OF COMPARATIVE ZOOLOGY. 63 
TOPOGRAPHY OF THE GALAPAGOS. 
As seen from the sea from the southeast, distant about ten miles, the 
western half of Chatham Island forms its principal and highest part. 
It rises more rapidly from its western extremity at Wreck Point to a 
height of 2,490 feet, as marked on the Admiralty charts. This summit 
is separated by a high land from the next highest point, which reaches 
an elevation of nearly 2,000 feet. From here the western mass gradu- 
ally falls with gentle slopes toward the east, and is separated by a 
low valley from the central mass, slightly undulating and with two 
nearly equal summits, which reach less than one third the height of 
the western half. This in its turn is separated from the eastern ex- 
tremity of the island, which is somewhat higher than the central mass. 
The southern slopes of the western mass of the island are covered by 
numerous small craters, and here and there its even outline as seen 
against the sky is interrupted by the sharp line of a smaller crater. 
Along the southern shore on the eastern half of the island there are 
a large number of the so called tuff craters, readily distinguished from 
the other craters, even at the distance at which we saw them, by their 
reddish color. They form a prominent line of well defined low, sharp 
cones, with more or less perfect craters. . 
Hood Island we did not visit. Captain Tanner, who passed a day on 
the island in 1888, says: “ It is low compared with-others of the group, 
its surface being covered with masses of broken lava rock. A little soil 
has formed between the blocks, in which bushes of various kinds find 
root, and during the season of rains lend a rich green hue to the other- 
wise barren surface. It is wholly devoid of fresh water during the dry 
season, and has no commercial value. Gardner’s Bay is a good anchor- 
age in the fine weather that usually prevails.” 
Indefatigable Island is perhaps the one of the Galapagos which best 
shows the mode of their formation. It forms a single mass, rising gently 
on all sides toward the great central plateau ; its sides are compara- 
tively little broken by lateral craters; the central plateau is sur- 
rounded by a series of rounded elevations, the remnants of the rim of 
the old crater. According to Mr. Cobos, after passing the lower line of 
the lava boulders one reaches, at about the same elevation as on Chat- 
ham and Charles, the plateau region, where the lava has become decom- 
posed into a most fertile soil, and for the size of the island its area 
fit for cultivation is quite extensive. The general character of the lower 
slopes, which reach to the water’s edge, do not differ from those of the 
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