VI NANDUA 87 



the main of fine palagonitic debris, with some fragments of min- 

 erals, &c, and contains a few microscopic tests of foraminifera. 

 This deposit passes down into apparently a rock of pure palagonite. 

 The succession of these beds and their characters are described 

 more in detail on page 344 ; and as indicated in the diagram there 

 given it is to be inferred that a very extensive formation of pala- 

 gonite has taken place on the surface of a submarine basaltic flow. 



On a similar slope of the Nandua district, and about half a 

 mile nearer Ndavutu, the pteropod ooze-rock overlies a coarse 

 zeolitic palagonite-tuff composed in great part of fragments of a 

 highly altered vacuolar basic glass, but without organic remains. 

 These tuffs are horizontally stratified. Tuffs precisely similar 

 occur on the northern slopes of Ulu-i-ndali three miles to the 

 south. They are all described in detail on page.335. 



Some miles up the valley of the Ndavutu River on the steep 

 slope descending from Vunivuvundi to the river, and on the sides 

 of the river lower down, are exposed dark palagonitic and some- 

 times calcareous clays and tuffs. I traced them as high as 450 feet 

 above the sea where they were bedded and dipped gently to the 

 west. In the river-channel they were mostly confined to the right 

 bank, the slope on the other side being strewn with large fragments 

 of columnar basalt. At the mouth of the Ndavutu River, there are 

 exposed tufaceous sandstones and a tuff"-conglomerate, probably 

 in great part formed of palagonitic materials, but I have kept no 

 specimens. 



There is much that is puzzling about the tuffs of the region 

 between Ndavutu and Vunivuvundi. The surface pteropod and 

 foraminiferous ooze-rocks, that are found here and on the Yanawai 

 or eastern border of the basaltic plateau and in other localities, 

 offer no difficulties ; but the origin of the palagonitic tuffs that in 

 places lie beneath them is not so easy to explain. At Mr. 

 Simpson's old estate on the Nandua flat one finds numbers of huge 

 blocks of columnar basalt scattered about on the slope descending 

 to the river ; and in places there is exposed in a small stream, up 

 to a height of 500 feet, a fossiliferous ooze-rock containing marine 

 shells. The ooze-rock is evidently an incrusting deposit ; but 

 when one goes down to the river-side, which is there about 200 feet 

 ibove the sea, one finds displayed in situ in the river-bed an 

 imygdaloidal basic lava with coarse tuffs and agglomerates a little 

 ower down. 



The Hill of Ulu-i-Ndall — The meaning of the name of 

 ;his hill is " Head of the rope." It is noted on account of the dense 



