764 SUB ANT ARCTIC ISLANDS OF NEW ZEALAND. [Soils and Soil-formefs. 



The matter insoluble after treating with HCl and HNO3 was evaporated to dry- 

 ness, treated with HF and H2SO4, dissolved in HCl, and fused with KHSO4, equalled 

 8*4 per cent., and was found to consist of titanium-phosphate.* 



ROCKS AND SANDS. 



Of considerable use in applied agriculture are various rocks and sands. One 

 need only mention phosphate rock, the source of mineral superphosphate ; lime- 

 stone or chalk, from which quicklime is produced; gypsum ("land plaster"), yet to 

 become generally used by farmers in New Zealand, but well known to fertiliser- 

 vendors as a suitable diluent for fertilisers ; and siliceous sands and gravels, exten- 

 sively used in peaty European soils. 



The chief desideratum in the work amongst rocks was, of course, the discovery 

 of a phosphate-deposit. The Campbell Island limestone bears a considerable re- 

 semblance to Milburn (Otago) rock phosphate, but analysis proved that the nuclei 

 which gave it so much the resemblance of phosphate were merely siliceous. The 

 content of silica in the samples of limestone examined was, indeed, enough to con- 

 demn the stone as a source of limestone for " burning." However, no doubt 

 deposits of suitable lime could be found on further search. Hector (23) mentions 

 the occurrence of true chalk, with large flints, at West Bay, Campbell Island, 

 where the cliffs are composed of chalk and flints on limestone. Small samples 

 of chalk (K 2649) were found by me, interspersed with clay, at Perseverance 

 Harbour. If the West Bay chalk is similar to this specimen in texture and 

 composition, it would make an admirable dressing for Campbell Island soils 

 without previous burning, if it were merely crushed up and spread on the soil, or 

 harrowed in."!" 



At the same spot in the clay were found beautiful blue granules of vivianite 

 (hydrated phosphate of iron). The occurrence of this is probably due to the 

 bones of animals, iron having replaced the calcium of the bone, a molecular 

 change which has been observed in moa-bones exhumed from swamps in New 

 Zealand. J 



Of less interest to the agriculturist is the occurrence of zircons (K 2620) in this 

 clay, from which they can easily be washed with water. Zircon (zirconium-silicate) 

 is a precious stone containing the rare element zirconium. Zirconia (the oxide) is 

 used to some extent in the incandescent method of gas lighting. 



An attempt has been made to collect evidence as to the method of weathering 

 of the rocks from these islands. Analyses of samples which showed weathering and 

 unaltered rocks side by side are given. 



* This has the composition 37'1 per cent. P2O5, 6r82 per cent. TiOj, 1'08 per cent, undeter- 

 mined ; is hygroscopic ; and has a specific gravity of 2-75. It may be the phosphotitanic 

 acid of W. Knop (Watts Diet, of Chem., Second Supp., p. 976), STiOj.PaOg, which contained 

 37-16 per cent. P2O5. 



I Chalk also occurs at Oxford, in Canterbury. For analysis, see Cox (24). 



J Vivianite has been reported from several localities on the mainland of New Zealand by Skey 

 (Colonial Laboratory Reports). An extensive deposit is said to have been found at Mercer, Auckland 

 in 1892, recorded by Park (.25). 



