186 



TRAVELS IN BRAZIL. 



pretty uniformly diffused over a great part of the 

 surface of the Morro de Villa Rica, covers the 

 older formations to the depth of from three to 

 twenty feet, and being so easily worked, has 

 peculiarly undergone considerable changes, through 

 the operations of the Mineiros. The flotz for- 

 mation consists of a clay, coloured red, more or 

 less, by oxyde of iron, but principally of litho- 

 marge. The colour of the latter is brick and 

 carnation, inclining to reddish brown, in many 

 places spotted with lavender-blue, and ochre- 

 yellow, and seems to be mixed with much yellow 

 earth. In this mass there is a great quantity of 

 blunt-cornered pieces of compact* brown iron- 

 stone, some small, others large, even to the size 

 of a foot and more. The brown iron-stone con- 

 tains many small drused cavities, filled with 

 brownish red iron-ochre ; it is often grown toge- 

 ther with greyish white quartz, which on the sur- 

 face is frequently reddish grey. There are also 

 seen in this flotz formation truncated pieces of 

 common ironglance of compact fracture, passing 

 into imperfectly conchoidal pieces of magnetic 

 iron-stone, mica-slate, detached nodules of quartz, 

 rarely fragments of topazes, one of which is pre- 

 served in the collection in Munich. The gold is 



* Though the whole flotz stratum is penetrated with an 

 iron-ochre, almost deep red, we met with no iron-stone, but 

 of a brown streak. 



