468 



Transactions. 



the cause of the phenomenon, it is interesting to note that the 

 Clarendon phosphate is similar in this respect to the deposits 

 of Ocean and Pleasant Islands. After making corrections for 

 other bases in the phosphate it is found that the CaO present 

 is always greater than the CaO which would be required to 

 neutralise the acids in the phosphate, thus : Ocean Island, 

 the excess is 6*8 per cent. ; Pleasant Island, the excess is 6 - 8 per 

 cent. ; Clarendon No. 1, the excess is 2*4 per cent. ; Clarendon 

 No. 2, the excess is 6-1 per cent. ; Clarendon No. 13, the excess 

 is 7*8 per cent. ; Clarendon No. 14, the excess is 9-4 per cent. 



Outcrops in the District. 



1. Williamson's Farm. — The outcrop has not yet been lo- 

 cated, but surface boulders and pebbles are abundant in the 

 fields below the road-line at some distance above Williamson's. 



2. Kiln Point. — At this, the first outcrop worked, the phos- 

 phate rests on the irregular surface of the limestone, the face 

 exposed being about 12 ft. high. The rock is mainly the high- 

 grade white variety, but it is mixed with brown sands and phos- 

 phatic green sands and clays, which diminish the average con- 

 tent of calcium-phosphate to such an extent that this outcrop 

 has now been abandoned in favour of the Round Hill quarry. 

 Rock-phosphate is exposed in a trench to the north of the point, 

 where it consists chiefly of the grit variety, mixed with phos- 

 phatic clays ; mammillary incrustations and cavities lined with 

 phosphorite are common in the trench. 



S.W. 



N.E. 



nr^i 



EZE 



t' 



CM' 



Face of Quarry at Kiln Point. 



a. Brown sands, b. Green phosphatic sands, c. Rock-phosphate. 

 d. Limestone, e. Basalt-fragments. 



A special feature of this outcrop is the presence of fragments 

 of basalt, from 05 in. to 45 in. in diameter, which are imbedded 

 in the middle of the rock-phosphate. They have the same charac- 

 ters as the basalt which is found a few yards farther up the 



