32 C. H. HITCHCOCK — GEOLOGY OF OAHTJ 



archipelago and to have been elevated as much as 800 feet, and Doctor 

 W. II. Dall presents tentatively the opinion that the fossil shells of these 

 beds may be of Pliocene age.* 1 have had the pleasure of examining these 

 limestones at Suva. Fiji, for as much as 500 feet of thickness, and am 

 satisfied that the Hawaiian terrane may be correlated with them, though 

 not so much elevated. Doctor Dall has recently examined the most 

 characteristic localities about to be mentioned, and has kindly stated 

 his views as to the age of the strata in his notes appended to this paper. 

 Owing to thorough disintegration, it is not easy always to discriminate 

 between a decayed lava and an earthy sediment, especially as lavas or 

 ashes are constant^ intercalated with strata. I will speak of these de- 

 posits at several localities where they may be easily examined. One of 

 the most important may be seen in a railway cutting a short distance 

 east of the Waipio station, west of Pearl cit}^, on the line of the Oahu 

 Railway and Land Company. The deposits seem to be arranged as fol- 

 lows from above downward : 



/. Ten feet of a reddish-yellowish earth, constituting the soil. 



H. Six feet of gray slaty colored earth. 



G. Two to 8 feet of limestone and marl. 



F. One to 2 feet of pure kaolin, best seen in the fields east. 



E. Three or 4 feet of bluish and other clays. 



D. Bed of oyster shells, I to 2 feet thick. 



C. Two and a half feet of ferruginous clay containing large nodular masses of 

 black hard clay, apparently carbonaceous. 



B. Six inches of greenish clay, with blue stains of what may be iron phosphate 

 or manganese oxide. 



A. Four or 5 feet thickness of clays, extending downward to the track of the 

 railroad and to an unknown depth. 



The uppermost of these layers may be followed along a sort of terrace 

 northerly to Oahu mill, and the gray layer shows itself wherever a cut 

 has been made deep enough to reach it. West of Oahu mill the kaolin 

 is recognized along the road leading west for one-fourth of a mile, and 

 also along the branch railroad half a mile out from Waipahu station. 

 It comes in contact with basalt, probably unconformably, along the rail- 

 road and overlies a pebbly rubble whose constituents are so decayed that 

 they will crumble under the pressure of the hand, and is over an ag- 

 glomerate that may be connected with the basalt. The Waipio cut is 

 repeated on a larger scale in a railroad cut easterly from the Ewa upper 

 pump (October 14, 1898). The basal greensand is thicker, as is the 

 kaolin, and the greater part of the upper material is a red earth, the ex- 

 posure here being about 40 feet thick. It is likely there is a direct con- 



•Amer. Jour. Sci., August, 1898, |fp. 165. 



