EXPOSURES ALONG ESTRADA CENTRAL OF PERNAMBUCO 



83 



originally deposited in water where clays alternated with the volcanic 

 ejectamenta that form the feldspathic beds. A prominent feature of 

 these bedded rocks is a felted appearance that is characteristic of the old 

 Paleozoic rocks through the highlands of Brazil. In the felted silicious 

 schists are occasional lenses or bands of flint or chalcedony closely re- 

 sembling novaculites, some of them more than a meter in length and 

 20 centimeters wide ; one was noted having a length of 3 meters and a 

 width of 2 centimeters. These flints are partly surrounded by and 

 partly penetrated by pink feldspars. The schists vary in color from 

 nearly black where they are unweathered to gray where they are 



Figure 14. — Looking west from* Antonio Olyntho. 



weathered. The black ones are exceedingly hard. The pink feldspars 

 are characteristic of all or nearly all of them, and many of them contain 

 quartz lenses. 



All of these bedded rocks are much jointed, the clean, smooth joints 

 cutting for the most part square across the beds. The joints are from 

 1 centimeter to 15 centimeters apart. 



The schistose rocks about Antonio Olyntho are slickensided. This 

 fact, together with the faults exposed at Antonio Olyntho and the gen- 

 eral structure, so far as it is visible between the Serra da Russa and the 

 west end of the valley, lead to the conclusion that the region is much 

 faulted, especially along the east-west belt crossed by the railway be- 

 tween Caruaru and Antonio Olyntho. 



According to the observations of Dombre, the granitic rocks found 

 about Bezerros continue to Sao Bento, about 40 kilometers south and a 



