58 E. 0, Teale: 



Howitt was a loose block, which had l)een brought to the old mine^ 

 As no more could be found in the neighbourhood, it was suggested, 

 that it might have come from Mansfield. 



The position of the present occurrence is shown on the map. It 

 is only about a mile in a straight line, south-east from Fry's, and 

 less than half a mile south-west from the old mine. 



The rock is light-coloured, creamish, earthy fi-agments predomin- 

 ating, but dark, almost black pieces sometimes somewhat cherty, 

 also occur. Rough stratification is noticeable, and the bed has a 

 defined dip and strike conforming with the enclosing rocks. The- 

 outcrop is not continuously exposed at the surface, and has the- 

 appearance of being broken and dislocated. The rocks in general 

 in this zone are nmch disturbed. The phosphatic breccia, however, 

 can be traced at intervals along a distance of about 130 yards, in a- 

 north-west to south-east direction. 



Wavellite is abundant in thin seams along some of the joint 

 planes, and an analysis of the sui'face I'ocks shows that it is an' 

 impure aluminous phosphate, containing only about 7% of P2^5. 

 This may represent leached material; at any rate, it would be un- 

 wise to say that it represents the composition of this rock at a 

 depth. Lithologically, the material does not resemble the Mans- 

 field phosphate rock, which is not a breccia. The organic remains^ 

 are imperfectly preserved crustaceans of the character of phyllopod- 

 like forms, while those of Mansfield have Ijeen referred to as prob- 

 ably Salterella, thus differing also organically. An account of this 

 phosphate deposit has recently been published. 2 



Since Tetragraptus has been recorded at Mansfield, it would^ 

 appear that both Lower and Upper Ordovician graptolite-bearing 

 rocks are closely associated. At the Howqua, the only fossils in the 

 associated beds are graptolites and occasional brachipods, which^ 

 may be either Upper Ordovician or Silurian, and the phosphate- 

 deposits are definitely interbedded with these. 



In order to test the relationship of the phosphate deposit to the 

 'surrounding sediments, the writer and his father spent a couple of 

 days with pick and shovel putting a trench across the outcrop, the 

 result of which was to prove conclusively that the phosphate breccia 

 is interbedded Avith the surrounding graptolite-bearing strata. The 

 accompanying section illustrates the relationship. 



Ernest W. Skeats and E. O. Teale, Aust. Inst, of Mining Engrineers. Proc. 

 New Series, No. 32, 1918, pp. 155-165. Fig. 4 is from a block lent by 

 the Aust. Inst, of Mining Engineers. 



