342 W. T. BRIGHAM ON THE VOLCANIC PHENOMENA 



of the United States Exploring Expedition," and in subsequent memoirs, has done much to 

 explain and extend our knowledge of the Hawaiian volcanoes. The information from these 

 two sources is scattered through many volumes, and it has seemed desirable to collect and 

 compare with the writer's own observations made during a residence of eighteen months, all 

 hitherto published on the Geology of the Hawaiian Group. 



KAUAI. 1 

 [See Map, Plate XL] 



General Features. — Kauai is from twenty-eight to thirty miles in diameter, nearly circular 

 in form, and has an area of six hundred and forty square miles. As will be seen, it forms 

 with Niihau, Lehua, and Kaula, a group closely connected in structure, as well as position. 

 As on the other Hawaiian Islands, two centres of formation may be noticed, and the 

 mountain summits are said to be thickly dotted with craters. Waialeale, the highest peak, 

 is situated a little east of the centre of the Island, and is supposed to be eight thousand feet 

 high. West of this is a high table-land more than four thousand feet above the sea, which, 

 extending over forty square miles, terminates in a precipice two thousand feet high. 

 Waialeale is much furrowed by deep valleys, the intervening ridges being sharp and irreg- 

 ular ; the lava of which the whole Island is composed is much decomposed on the surface, 

 and where not covered by the profuse vegetation of the tropics exhibits strata with a 

 gradual dip of from 5°-10° towards the sea on every side. 



On the coast of the north eastern to the south-eastern part of the Island is a ridge, inter- 

 rupted in many places, and of no great height, but seemingly detached from the great central 

 mountain, being placed tangentially to the main ridges. The shore on the western side is 

 precipitous, but elsewhere it is a sand beach interrupted by basaltic cliffs from ten to a 

 hundred and fifty feet in height. The valleys are long, widening towards the sea and very 

 fertile, the soil being sometimes ten feet deep. The rivers on the windward side of the 

 Island are numerous, although not large, and as most of the low land lies on that side, 

 Kauai possesses a larger proportion of arable land than any of the other Islands. The 

 south-west, or leeward district, is dry and barren, although several rivers descend from the 

 mountains above. 



It is more difficult to trace the original plan of Kauai than of any of the other Islands, as 

 its mountain summits are difficult of access, its valleys and ridges larger and more irregular, 

 the lavas more decomposed, and the natural sections more concealed beneath the vegetation 

 than on any other Island of the Hawaiian group. From the degradation of its ridges, and the 

 absence of any very recent volcanic products, it has been supposed to be the oldest member 

 of the group, and it cannot be disjmted that volcanic action ceased here before it became 

 extinct on 0£hu or the other Islands. Many years must have elapsed, — how many it is 

 useless to conjecture, — to convert the hard basaltic lava into the rich soil which nourishes 

 trees of immense size ; and which is so abundant as to give Kauai the name of The 

 Garden. 



1 The most northerly island of the group, Nih6a or Bird the egg-i which the birds deposit there in large quantities, it 

 Island, lias never been visited by scientific men, but from the would seem to be the remains of an ancient crater, as it ex- 

 description of natives and others who have landed to collect hibits tufaceous and basaltic formations. 



