472 



Transactions. 



11. Millburn Lime Quarry. — Two boulders of phosphate 

 occur here, resting on the irregular surface of the limestone. 

 On the spur across the gully, north-west from the quarry, there 

 is a prominent outcrop of phosphate, which so far has not been 

 worked. 



s.w 



■ 300 -Fe^t, 



a. Brown sands. 



Face at Millburn Lime Quarry. 



c. Rock-phosphate, d. Limestone, h. Phosphatic clay 

 nodules. 



12. Campbell's. — Opposite Sutherland's quarry, on the north 

 bank of a small creek, there is a massive outcrop of rock-phos- 

 phate, 20 ft. high, resting on the limestone ; it has not yet been 

 worked. 



13. Quill's. — A few tons of phosphate have been taken 

 from here, but apparently there is not much of it. 



14. J. Gray's. — This has been worked to a slight extent, 

 but the phosphate, which here rests on glauconite sands, is low- 

 grade, patchy, and composed mostly of grit phosphate and 

 clays. 



Origin of the Rock-phosphates. 



Several theories have offered themselves as explaining the 

 origin of these deposits : they may be summed up as follows : — 



(1.) That the boulders were transported to their present 

 position from a distance, by an agency such as running water. 



(2.) That they were formed in situ, as the result of concre- 

 tionary action around some nucleus. 



(3.) That they were formed in situ by deposition of phosphoric 

 acid (P 2 5 ) from ascending waters. 



