12 



FOTE. 



raphy carved on gabbroid rocks, which has been flooded by later 

 andesites. Slates and red sandstones were found in the stream beds 

 associated with the diorites and gabbros. One diorite boulder had 

 an inclusion which resembled slate. The actual contact of these 

 rocks was not seen, but, from the inclusion of slate in the diorite, it 

 is inferred that the plutonic rocks intrude the slates and sandstones. 

 The andesites which flooded the gabbro hills were later eroded and 

 depressed beneath the sea. At a water-fall on the northern side of the 

 Singatoka, a coralliferous limestone mingled with pebbles of the 

 andesites lies unconformal)ly on the lava flows. The basal layer is 

 but two or three feet in thickness and gratles upward into a sandstone 

 which is overlain conformably by marls and claystones. Occasional 

 beds of brown coal, a few inches in thickness, are interbedded with the 

 marls. 



The lava flows represent a thickness of 300 or 400 feet, while the 

 marls and sandstones are 500 or 600 feet in thickness and are over- 



FiGURE 1. Cross-section of Falls Contact, near Wai Mhasanga, Viti Levu. 

 1 — Gabbro and syenite hills. 2 — Andesitic flows. 3 — Basal conglomerate 

 (2 feet) with coral heads. 4 — Marl. F> — Claystone and marl with occa- 

 sional brown coal seams. 6 — Massive hmestone. 



Iain conformably by 200 or 300 feet of a massive-bedded limestone. 

 The dips of these rocks are .50° to 8-5° N., and their general strike 

 somewhat north of east. The limestones are frec^uently so folded that 

 they are transformed to blue marble. Masses of the limestone form 

 residual, flat tops to many of the interior hills, each covering areas 

 two or three square miles in extent. The sketch shows the rock rela- 

 tions at the contact near the falls. (Figure 1.) 



About 12 miles from the present southwestern coast-line of the 

 island, near the small town of Tumbairata, the rock types just de- 

 scribed disapiK-ar and volcanic agglomerates and ash-beds replace 

 them. No contacts were seen, but as the dips of the ash beds were 



