E. C. HARDER AND R. T. CHAMBERLIN 



389 



ore fragments and soft ore, the latter acting as a matrix. On the 

 other hand, deposits consisting largely of soft ore may- have hard 

 ore lenses interbedded with the soft ore. 



The soft, powdery ore is known among the natives of the iron 

 region as "jacutinga," and since this term has also crept into the 

 literature its meaning should be clearly defined and its misuse 

 avoided. The term "jacutinga" was appHed by Hussak' to 



Fig. 13. — The Peak of Sao Luis near the village of Agua Quente. In front of the 

 peak is a plain surfaced by canga. The steeply inclined beds of iron formation which 

 appear in the peak continue under the canga covering of the plain. In the peak they 

 consist partly of itabirite and partly of hard ore; under the plain the same beds consist 

 of soft, powdery ore and soft itabirite. On the extreme left is the Caraga quartzite 

 range. 



certain gold-bearing portions of the iron formation. The jacutinga 

 thus designated occurs in the form of shoots and irregular masses 

 inclosed in itabirite from which it differs in a minor way only. It 

 has a variable composition, and its principal characteristic is a fine 



^ E. Hussak, "O Palladio e a Platina no Brazil," Annaes da Escola de Minas de 

 Ouro Preto, N. 8 (1906), p. 96, tr. by Miguel A. R. Lisboa, and Manoel A. R. Lisboa. 



