O'Eeilly— Oyj the Phosphorite Nodules of Podolia. 217 



at the centre being in this case of crystalline foliated calcspar of a 

 bright-grey or greyish-brown colour, showing generally a star form. 

 In others the radiated structure is equally distinct all through, 

 and at the centre is found a star-formed hollow space, filled with 

 a brown earthy mass. The former generally presents a more 

 greyish colour; the latter a very distinctly brown colour. Be- 

 tween the radiating fibres or bands occur various enclosed mine- 

 rals, such as calcite and plates of pyrites, little grains of quartzote, 

 small quantities of a yellow powder, composed of manganese car- 

 bonate, a dark-brown pulverulent mass, which is a mixture of iron 

 oxyde and carbonate of iron, and finally an aluminous silicate in 

 the form of a white earthy mass. Occasionally particles of galena 

 occur sprinkled through the mass. 



Several Tables of Analysis are given, one of which gives in 

 constituents the composition of the inner and outer zones of the 

 specimen analysed ; another that of the core or kernel ; and 

 another that of the matrix of the phosphorite, which shows whence 

 the phosphoric acid proceeded. 



I. — Constituents of the Outer and Inner Zone of a completely- 

 altered Phosphorite Ball of 15 cm. Diameter. 



