BY D. MAWSON. 439 



Fatmalapa appears to be overlaid by a couple of hundred feet of 

 tuffaceous agglomerate. 



Newer raised reefs occur at intervals in terrace-formation 

 down to the beach,* evidently marking a succession of sea-levels 

 resulting from, sudden uplifts of the land, probably quite parallel 

 with those recorded at Port Resolution within recent years. 

 When the time that elapsed between any two succeeding uplifts 

 was considerable, the resulting coral reef-growth would be cor- 

 respondingly extensive; in a case where several lesser upheavals 

 taking place within a few years of each other have contributed 

 to the total elevation, little trace of these intermediate beach- 

 lines could be expected preserved now, after exposure to a tropical 

 denudation for many years. Special attention was paid to this 

 point, and as a result we are able to say with certainty, from the 

 evidence of corrosion-marks in the terrace-faces, that at any rate 

 the more recent of them were elevated by a succession of minor 

 upheavals following each other at intervals, very short compared 

 with the periods of time elapsing between the major upheavals 

 resulting in the formation of distinct terraces. The evidence of 

 these minor uplifts is only faintly marked, even in the case of 

 the more recent upheavals; it has been completely obliterated in 

 the older raised reefs. 



On account of the steep shore-slope and continuous upheaval, 

 the reefs have narrow platforms which are usually level or even 

 gently rising towards the land; where the platforms are wider, 

 however, they may be noticeably depressed on the landward side, 

 indicating the existence formerly of a calm-water channel. 



Most instructive sections of the coral veneers are exposed in 

 several localities where they have been cut through by torrential 

 watercourses, notably at Steep Gully (Plate xxiv.). Such sections 

 show that after an upheaval, the coral begins to grow in the 

 shallower water, building directl}' on the solid rock below, or, as 

 is more often the case, separated from it by a few feet of beach 

 sand or beach pebble conglomerate. As the reef continues to 



* See Plate i. in 'Preliminary Note.' Report A.A.A.S. x. 1904. 



