192 



BRANNER 



rest of the way to 

 Theophilo Ottoni. At 

 Maj-rink station the 

 rocks are quartz-monzo- 

 nites and coarse-grained 

 gneiss. In the bed of 

 the stream there are 

 good exposures showing 

 the banding of the rocks 

 to strike N. 25° E. 

 From where the railwa}' 

 enters the narrow Mu- 

 cury valley at kilometer 

 172 to kilometer 345 the 

 rocks are all either 

 quartz-monzonites, gne- 

 isses, or granites, the 

 quartz-monzonites pre- 

 dominating. I was un- 

 able to learn anything of 

 the relative ages of these 

 cr\'stalline rocks. The 

 bed of the Rio Mucury 

 is everywhere of these 

 massive rocks. Here 

 and there hills of the 

 bare, rounded rocks are 

 exposed in the sides of 

 the narrow river chan- 

 nel, and enormous ex- 

 foliated boulders are 

 abundant throujrhout the 

 area of crystalline rocks. 

 There are some fine ex- 

 amples of these boulders 

 at Bias Fortes, kilometer 

 30S. In this lower por- 

 tion of the crystalline 



