314 NOTES OF A NATURALIST. 



range. The outlines were in most places rounded and 

 covered with vegetation, but at intervals occurred 

 steep conical masses, of the same general type as the 

 sugar-loaf peaks surrounding the Ba)?- of Rio Janeiro. 

 However steep, the rocks nowhere showed angular 

 peaks or edges, these being always more or less 

 rounded. 



It would be rash to generalize from the partial 

 observations of a passing traveller ; but the broad 

 outlines of the geology o^ Brazil, or, at least, of the 

 eastern provinces, have now been well traced,* and 

 some general conclusions may safely be drawn. It is 

 true that large districts of the interior have been but 

 partially explored, and remain blanks on the geological 

 map ; but the eastern half of Brazil is undoubtedly 

 ancient land; presenting no trace of secondary strata 

 except in small detached areas near the coast, and 

 where more recent tertiary deposits are to be found 

 only in a portion of the great valley of the Amazons. 

 A mountain range, having various local designations,- 

 but which may best be called the Serra da Manti- 

 queira, extends from the neighbourhood of San Paulo 

 to the lower course of the Rio San Francisco, for a 

 distance of twelve hundred miles, and this is mainly 

 composed of gneiss, sometimes passing into true 

 granite, syenite, or mica schist ; and the same may 

 be said of the Serra do Mar, a less considerable range 

 lying between the main chain and the coast. The 



* The best general account of the geology of Brazil that I have seen 

 is contained in a short paper by Orville A. Derby, entitled, " Physical 

 Geography and Geology of Brazil." It was published in the Rio Navs, 

 in December, 1884, and, through the kindness of Mr. Geikie, I have 

 seen a reprint in the library of the School of Mines. 



