TRAVELS IN BRAZIL. 



291 



racter of the scaly and earthy lithomarge in which the 

 topazes are found in Capao and Lana. Though generally 

 white, it is often tinged yellowish and greenish by oxyde of 

 chromium, sometimes it alternates in thin strata with the 

 granular quartz, and approaches the quartz-slate incumbent 

 on this clay-slate. This scaly and earthy lithomarge, to- 

 gether with the friable granular quartz, has given occasion 

 to the notion, that chromate of lead was found in Brazil in 

 soap-stone, in pot-stone, in scaly talc, and in sandstone, and 

 led Mr. Zinken to take the pulverulent coat (earthy litho- 

 marge), which he had remarked, for kaolin. On the whole, 

 we found that the mode of occurring, as well of the red as 

 of the green chromate of lead, at Cujabeira, perfectly coin- 

 cides with that at Beresof, on the Ural, in Siberia, which 

 grows in quartz veins in the talc rock, mixed with grains of 

 quartz, or, as Pallas expresses himself, on veins of shat- 

 tered and drused quartz, in a white and yellow brown, soft, 

 rather fibrous * and micaceous clay-rock. The resem- 

 blance of the lithomarge of Cujabeira to that of Capao, in 

 which the topazes are found, appears the more worthy of 

 remark, because Pallas mentions, that topazes are likewise 

 found single and collected, in drused cavities, at Beresof, in 

 Siberia, in the gold veins. 



Note I. 



At Antonio Pereira, heavy spar likewise occurs, which is 

 of a greyish white colour, in pieces of a fine and coarse 

 grain, is easily separated, very transparent, and, as Mr. 

 Zinken justly observes (in the account of Portugal and its 

 colonies, p. 26.), bears the same relation to the scaly heavy 

 spar as coccolite does to augite. 



* In the original, fadenhaft, fibrous or stringy ; but I am 

 unacquainted with the mineralogical meaning of the term. 

 Trans, 



U S 



