354 On the Pa rag en e tic Relations of Minerals. 



The iron oxides then contain at least traces of manganese, 

 while the manganese oxides are free from iron. This fact 

 is in accordance with the chemical fact, that when a solution 

 of iron and manganese peroxides is treated with ammonia, 

 the iron is first precipitated. However, at the Thuringer 

 wald, hematite appears to follow manganese oxides, but this 

 may be connected, in some manner, with the subsequent dis- 

 locations which the lodes have suffered. 



There are many lodes in which iron oxides or manganese 

 oxides occur separately. They appear in Saxony to be iden- 

 tical with amethyst lodes, in which manganese or iron oxides 

 occur. 



This formation is closely connected with barytite, and it is 

 known that baryta is present in most ores of manganese. 

 However, the barytite is always implanted upon the manga- 

 nese, and for this reason it will be treated of in the next 

 section. Barytite has been observed implanted upon hema- 

 tite, which occurs, on the other hand, above fluorite and 

 calcite, as do manganese oxides above calcite, although indeed 

 the former presence of these spathic]minerals may only be in- 

 dicated by pseudomorphs. The paragenesis of manganese 

 oxides with calcite is remarkable. Pyrolusite and varvicite, 

 which have originated from manganite, occur pseudomorph- 

 ous after calcite, the apices of the scalenoedrous still con- 

 sisting of calcite, and the metamorphosis may easily be seen 

 to have originated from the saalbands. 



It would seem that this formation belongs to nearly, if not 

 the same period as the fluo-barytic, barytite appearing as 

 the latest member ; but a closer acquaintance with the for- 

 mation must decide this point. 



The most recent rock in which the manganese and iron 

 formation occurs is phonolite. 



The general peculiarities of the lodes of this formation are 

 as follow : — 



1. Sulphurets are almost altogether absent. 



2. Pseudomorphs are more numerous here than in any 

 other formation. It may without exaggeration be said that 

 there is not any manganese lode in which at least one kind 

 of metamorphosis has not taken place. The majority of 



