KAUAI. 275 
island. The effect of the growth of vegetation upon it, in bringing 
the iron into new combinations with organic acids, is seen about 
Koloa, where there is a foot or so of dark loam. The cavernous sur- 
face of the lavas appears to soak up whatever waters fall, and the 
region is mostly barren, except in the immediate vicinity of Koloa, 
where there is a fine stream and some marshy soil. 
Other lateral cones were said to exist near Wailua, in the southwest 
part of the island; but they were not examined by the author. 
ad. Coral Formations. 
The shores of Kauai are bordered by a narrow growing reef of 
coral excepting on the side of the mountain cliff, where the shore is 
too abrupt. ‘The most important effects derived from these reefs, are, 
the accumulation of coral sand on the beaches, the protection of the 
coast from degradation, and the enlargement of the island through 
the stoppage of the detritus brought down by the rivers, as well as by 
beach accumulations. 
The beaches of coral sand are quite extensive on the eastern or 
windward shores, and a low ridge continues along, seldom inter- 
rupted, except by an occasional jutting point of black rock. This 
ridge is raised from ten to twenty feet above high tide, and, in some 
places, where drifted by the winds, the height is thirty to thirty- 
five feet. ‘There are remarkable hills of this extent on the southwest 
coast. 
About the mouths of the streams, the sands are often thrown up se 
as to close the stream entirely, as far as appears at the surface, and 
deltas of small extent are sometimes formed. At the opening of the 
Hanalei Valley, which forms a small bay, a tract nearly four square 
miles in extent has been made through the agency of the sea, winds, 
river, and reefs, and upon this plain the fine village and rich lands of 
Waioli are now situated. The land, through the gradual extension 
of the beach, has advanced about a mile to seaward. The river banks, 
which vary from two to ten feet in height, expose the stratified coral 
sand in numerous sections, and they present often a thin lamination, 
with all those irregularities of dip and direction which may be found 
in a beach, and with a slope, in general, to seaward. This slope, 
though, at times, nearly horizontal, more commonly amounts to eight 
or ten degrees. ‘The sands are either loose, or aggregated into brittle 
