Andrew. — On the Clarendon Phosphate-deposits, 449 



of his own. And yet a third thought that a reddish clay on his 

 property might prove to be a red variety of the eagerly sought 

 rock : the clay was due to the weathering of a basalt rich in 

 iron. 



Previous Investigation and Literature. — The district has been 

 exceptionally free from geological investigation, and until the 

 discovery of rock-phosphate attracted little attention. In 1862 

 Dr. Lauder Lindsay is reported to have delivered a lecture 

 on " The Geology of the Tokomairiro and Clutha Districts," 

 and to have mentioned the limestone at Millburn. I have been 

 unable, however, to see an account of his lecture. In the Report 

 of the Geological Survey for 1873* the " calcareous sandstone 

 of Waihola Gorge " was mentioned, but no description was 

 given. In 1875 Captain F. W. Hutton gave a passing notice 

 to the limestone of Millburn| ; he mentioned the occurrence 

 of " an isolated patch of limestone on the side of the road at 

 Waihola Gorge " ; he noticed the occurrence in it of Ostrea 

 widlerstorfii and Lima keoigata. Sir James Hector travelled 

 through the district, but apparently saw nothing worth men- 

 tioning. In his " Outlines of New Zealand Geology "J there 

 is no reference to Millburn or neighbourhood. In 1902, soon 

 after the discovery of the rock-phosphate, Professor James Parkf 

 visited the locality, and his report on the geology of the phos- 

 phate-deposits, published in 1903, was the first systematic de- 

 scription of the geology of this district. 



Physical Geography. — To the south of Dunedin there is a 

 line of coast-hills, varying in height from 500 ft. to 1,400 ft. 

 Shut off by these hills from the sea are two long, somewhat 

 narrow plains — the Taieri and the Tokomairiro — along the length 

 of which run the main road and the Main Trunk Railway. The 

 drainage of these plains finds an outlet to the sea through nar- 

 row gorges in the coast-hills. On the western side of the plains 

 the hills rise abruptly, but between Clarendon and Millburn they 

 jut far out towards the east, separating the two plains from each 

 other, and forming the Waihola Gorge — the former name for 

 Millburn. It is at the base of the protruding part of these 

 western hills that the rock-phosphate mostly occurs. On the 

 southern (Millburn) side of the gorge the hills rise sharply at 

 first till the crown of the spur is reached, and then the spur 

 runs in a north-west direction, attaining its greatest height at 

 the Trig. Q. From the trig, another long spur runs clown in an 



* Report Geological Survey N.Z. (1873-74): Progress Report xiii. 

 t Captain Hutton, " The Geology of Otago " (1875), p. 48. 



J Sir J. Hector, " Outlines of New Zealand Geology " (1886). 



§ Professor James Park, Trans. N.Z. Inst. (1902), vol. xxxv, p. 391. 



15— Traus. 



