V BY H. J. JENSEN, D.SC. 73 



The Challenger soundings off the Cape Agulhas Bank 

 brought up phosphatic nodules and glauconite sand from a 

 depth of 1,900 fathoms. Murray and Renard show that 

 such deposits form particularly off continental borders and 

 where currents of different temperatures meet, and where 

 consequently great destruction of organic life is going on. 



GUANO DEPOSITS. 



Guano may often occur unleached on rainless islands 

 or in rainless coast districts, as on or off the west coast of 

 South America. It may also occur in caves, as at Olsen's 

 Caves near Rockhampton, Queensland. It is composed 

 chiefly of the excrement of seabirds when found on islands 

 or on the coast, and when found in caves it is usually the 

 dung of bats. 



WHERE PHOSPHATES MIGHT BE EXPECTED IN 



AUSTRALIA. 



(A) Apatite. — In many parts of Australia we have 

 Archoean, Cambrian and ancient paloeozoic schists and 

 gneisses intruded by gabbroic plutonic rocks. In the Mount 

 Lofty Ranges and Yorke Peninsula of South Australia, the 

 Australian Alps of New South Wales and Victoria, in the 

 Broken Hill district, in both Southern and Northern Queens- 

 land, very ancient schist formations are met with, and 

 where such formations are intruded by highly titaniferous 

 gabbros and norites apatite veins might be expected. In 

 the Northern Territory of South Australia and Western 

 Australia it is likewise possible that apatite veins of commer- 

 cial value may yet be found. 



The country lying to the west of the D'Aguilar Range 

 in Southern Queensland consists largely of gneisses, amphi- 

 bolites, and schists, having an older appearance than any 

 other met with in Australia. In many localities in this 

 area the schist formations are intruded by gabbross. and 

 the entire area being a titaniferous province, the chances 

 of finding payable apatite here are not bad. This is the 

 only likely locality with whose detailed geology I am 

 personally acquainted. 



(B) Phosphorites. — These minerals might be met with 

 in pockets in any of the Paloeozoic limestones of Australia, 

 and possibly as beds in such limestone. Many of our 

 Cambrian, Silurian and Devonian limestones were re- 



