314 Brannev — Geology of the Hawaiian Islands. 





Well horings on Oahu. — 

 Several records of wells 

 bored for water near Hon- 

 olulu are given by Dana 

 and Hitchcock.* In addi- 

 tion I have, with the aid of 

 Mr. Fred E. Harvey of the 

 Government Survey, been 

 able to collect several others, 

 and these records, about for- 

 ty in all, have been plotted 

 to scale for the purpose of 

 attempting a correlation of 

 the beds penetrated. It was 

 found that the characters 

 of the materials .passed 

 through as rej^orted are not 

 sufficient to warrant corre- 

 lation. Herewith are given 

 four of the sections that 

 appear to resemble each 

 other closely. They are all 

 in the city of Honolulu. 

 The enormous quantity of 

 water flowing or being 

 pumped from the wells on 

 Oahu aiford a valuable con- 

 tribution to our knowledge 

 of subterranean waters. It 

 is to be noted that in every 

 instance the wells penetrate 

 beds of coral or other cal- 

 careous rocks. These rocks 

 appear to be built round the 

 volcanic core of the islands, 

 but they are sometimes in- 

 terbedded with lavas, tuffs, 

 or water -worn bowlders. 

 The chief rainfall is in the 

 mountains, but the waters 

 follow down the valleys, 

 sink into porous beds that 

 occupy the lower ends of 

 the valleys and pass seaward 

 as underground waters. It 



* Geology of Oalm. Bui. Geol. 

 Soc. Amer., xi, 15-17. 



