428 Proceedings of the Royal Physical Society. 



of The Peak. Look Out Hill, of conical form, obtains its 

 name from a hut on the summit, which is used as a watch- 

 house. Immediately north of the base of Tangle Eock is 

 a smaller rounded eminence, and lastly, a little hill with 

 loose masses of phonolite on its summit, lies not far north of 

 Leao Bay. Outcrops of phonolite occur on all those hills, 

 but the character of the rocks underlying the deep red 

 vegetable soil covering the level ground between them is 

 difficult to determine. The western coast is lined with 

 cliffs, or, at least, very steep rugged slopes, but there is 

 generally a beach beneath them, at any rate at low water. 

 At this season of the year a fine sand, composed almost 

 entirely of shell fragments with a few grains of hornblende, 

 covers the beach all along the north-west coast from Portu- 

 guese Bay eastwards, as well as various other points on both 

 the southern and eastern shores. Just south of the north- 

 east point, and also at Sambaquilbaba on the north-west 

 coast — where there is a small settlement — immediately in- 

 land from Leao Bay, the sand is blown into dunes, which, 

 in the two last-mentioned places, are planted with cocoa-nut 

 palms. In the north-east it shows traces of incipient con- 

 solidation in the shape of waved and branching streaks of 

 agglutinated sand traversing the mass. A calcareous sand 

 rock occurs at various places on the mainland ; the deepest 

 deposit is on Tobacco Point, where it forms cliffs of consider- 

 able height. It is seen also at the base of Look Out Hill, 

 and in small quantity on the east coast. A considerable 

 mass of it is presented at the south-west corner of Eat 

 Island, and Booby and Egg Islands are entirely composed 

 of the same material, of which a deposit overlies the basalt 

 of Platform Island. In the entry to Leao Bay there is 

 an islet consisting of this rock overlying phonolite. It 

 weathers in a curious manner, and its surface becomes 

 covered with sharp, rough, jagged points, one, two, or three 

 feet high, with deep holes between them, so that it is ex- 

 tremely difficult to walk over. In the " Challenger " reports 

 this is mentioned as resulting from the consolidation of blown 

 sand, and certainly the incipient solidification seen in the 

 dunes of the north-east, appears to favour this theory. But 



