u 



rUOFKSSOlf W. J. SOLLAS. 



c uitiuuoiisly beneath the saiul of which thus islet consists, till it passes into the 

 platform of the lagoon. The habitable land of the reef thus rests upon a foundation 

 of consolidated coral breccia, calcareous sandstone and cono^lomerate ; these formincr 

 a series of deposits of no great thickness, as is shown by the fact that in neither of 

 onr l)ore-holes were liard rocks encountered for many feet below the surfi^ce. 



The history of this superficial sheet of rock is a matter which demands a careful 

 investigation, and we shall find many problems involved in its study. One of the 

 first facts to arrest mv attention in mv wanderings on the lagoon side of 

 Funafuti islet was the constancy with which the slabs of coral which form much of 

 the breccia beds slope towards the ocean ; in many cases they are arranged in 

 imbrication one upon another, all sloping in the same direction away from the lagoon. 

 This disj)osition is rendered all the more striking by contrast where the hard rock 

 protrudes from a bank of loose pebbles forming the existing beach ; the pebbles 

 slope towards the lagoon, tlie coral slabs away from it (fig. 5). Repeated observa- 

 tions showed that this arrangement is general, and not confined to one locality ; 

 further, In the ease of Pava it Is continuously maintained beneath the islet from the 

 lacjoon to the ocean side. 



Fig. 5. — Lagoon cliff of consolidated coral rock north of the village of Funafuti. The slabs of coral 

 in the rock dip oceanwards ; the pebbles of the modern beach towards the lagoon. 



Cases occur In which the hard rock crops out on the ocean side of the outer ridge ; 

 the coral slabs and the pebbles of the beach have then the same direction of slope 

 (fig. 6). 



Fig. G. — Cliff of coral-rock pi'ojccting from the side of the outer ridge, here formed of large pebbles. 

 The pebbles and the elongated fragments in the coral-rock both dip in the same direction, ocean-wards. 



