TicHBORNE — On an Argentiferous Galenetic-hknde. 303 



calculate that there are about 1,000 tons in sight. The bluestone 

 seems to he surrounded by coal, with veins of bluestone on the 

 north, and on the south side blue slate, and ■white micaceous schist, 

 and deeper down comes iron pyrites." 



Of course, from a commercial point of view, the amount of silver 

 found in this ore is the most important item of the analysis. Our 

 analysis gives rather different results from those obtained in the 

 Welsh mines, but they do not agree at all with the analyses given 

 in the notes to Mr. Argall's Paper. Five analyses are given, and 

 silver is only mentioned in three out of the five, which give respec- 

 tively 5, 7-i-, and 6 ounces per ton\ From reasons which we shall 

 shortly state, we think it probable that most of the samples must 

 have been not only poor in silver but very indefinite samples of the 

 bluestone. It may be interesting to compare this argentiferous 

 ore with some others which are well known and worked for their 

 silver. The following figures are taken from Dana's Mineralogy, 

 5th edition : — 



The last-named Ovoca ore compares very favourably with the 

 above list, which includes some of our great sources of silver. If 

 we examine this mineral with the naked eye, particles of pyrites 

 may be seen scattered through the mass in an accidental and rather 

 erratic manner. The remainder of the mineral is, however, remark- 

 ably homogeneous, and will bear examination under the microscope 

 by reflected light with considerable impunity. The silver exists as 

 sulphide, because dilute sulphuric acid does not dissolve any trace 

 of that metal from the mineral. 



The actual composition of this ore brings us to the consideration 

 of two points, viz. : — (1) How far we should be justified in con- 

 sidering it as a distinct mineralogical specimen ; (2) The construc- 



^ Since this Paper went to Press, samples of the ore have been assayed in London, 

 giving as high as 9 ozs. of silver per ton, and also containing 1 dwt. of gold. 



