ROCK PHOSPHATES OF S. AUSTRALIA. 24:1 



samples on analysis were found to contain hydrous phosphate of 

 alumina instead of phosphate of lime; this mineral is also associated 

 with the phosphate rock at Clinton. 



The deposit occurs in limestone, quartzite, sandstones, and slate 

 formations of the same geological age as those of Clinton and Bright. 

 The limestone bounds it at a distance on the east-north-east and north 

 sides at a low elevation, while the quartzite and slate occur as isolated 

 hills of small extent on higher ground. The ground between the out- 

 crops is more or less thickly covered with an ovei'-burden of soil and 

 detritus. The workings consist of quarries, shafts, and tunnels. 



This deposit, besides containing massive rock and segregated 

 masses and nodules, consists largely of a softer friable formation, 

 which is worked by means of galleries or drives about 50 ft. below the 

 surface: it apparently fills a wide interval between the soft argil- 

 laceous and arenaceous beds on the one side and the limestone on the 

 other; it is being extensively worked, and its limits, both laterally and 

 in depth, have not yet been determined. 



Analyses of samples showed from 58'9 to 77'9% tricalcic phos- 

 phate. 



In this district, i.e., Kapunda and Belvidere, five other large 

 deposits have been opened out and worked upon- -viz., St. Kitt's, 

 Allandale, Koonunga, Green's Freehold, and Moculta ; they are all 

 somewhat similar in character to- St. John's. 



Bendecby. — About 8 miles east of Carrieton Railway Station, or 

 about 180 miles north of Adelaide. 



Phosphate has been found here in two localities two miles apart; 

 it outcrops in irregular-shaped veins and masses in claystone and clay. 

 The country rock consists of dolomitic limestone, of the same 

 geological age as that of Clinton, argillaceous limestone and clay slate 

 striking north-north-east and dipping west-north-west at a high incli- 

 nation. The phosphate rock, as usual, is found chiefly in conjimction 

 with the limestone, and appears to occupy places in the bed rock, 

 which were originally open cavities. 



Analyses gave from 12'4 to 73'1% tricalcic phosphate. 

 Hundred of Cunningham. — Near Ardrossan, Yorke Peninsula. 



Phospiiate rock occurs here, associated w'th argillaceous, arena- 

 ceous, and calcareous beds in Cambrian limestone. Analyses gave up 

 to 82% tricalcic phosphate, the deposit also containing a large 

 quantity of lower grade rock. Phosphate of alumina also occurs in 

 this locality. 



The character of the above deposits is that of large masses 

 occupying what were apparently at one time either caves and hollows 

 in the Cambrian limestone, or segregated and diffused through the 

 accompanying argillaceous and arenaceous beds ; which have near the 

 surface been redeposited as a secondary formation through the clay 

 and sandy detritus resulting from denudation. 



Development in depth has not gone far enough to show definitely 

 whether the phosphate rock will in depth ecsist as iuterstratified beds 

 or lode-like formations. Indications of this are, however, afforded by 

 more re<:ent discoveries, where deposits which have a similar character 



