A NATURALIST IN BRAZIL 



as the Frankfurt scientist Otto Maull recently demonstrated, is a 

 vast body of primitive gneiss, which in the course of the ages has 

 been repeatedly uplifted and depressed. During the later geological 

 periods the sea invaded the more depressed areas. And since in the 

 sea the fine ooze brought down by the rivers is continually sinking 

 to the bottom, covering the bodies of animals which have also sunk 

 to the bottom, and preserving their harder portions, we are able to 

 ascertain, from those remains, which are now scattered over the 

 surface of the continent, the enfolding ooze having ages ago hardened 

 into rock, that America has passed through all the geological epochs 

 of which we find evidence in other parts of the world. It knew the 

 Carboniferous, the Jurassic, and the Cretaceous periods, and the 

 cretaceous deposits are spread all over the north-east of Brazil, 

 which must at one time have been covered by a wide sea, in which 

 swarmed sea-lizards of enormous dimensions. The next geological 

 period, which we call the Tertiary, and which witnessed the 

 emergence of the mammals, has likewise left its deposits in Brazil, 

 as one may see on approaching the north-eastern littoral, where the 

 steeper slopes of the coast are as white as snow. It was during this 

 period that those tremendous foldings of the earth's crust occurred, 

 which, to the accompaniment of volcanic outbreaks in the western 

 part of South America, simultaneously with similar outbreaks in 

 North America, piled up the Cordilleras. 



Brazil was a quieter land than the western side of the continent, 

 which even to-day is so subject to earthquakes. Its mainland, rising 

 to altitudes of 1,500 to 2,500 feet in the centre, has sunk towards the 

 basins of the Amazon and the Rio de la Plata, so that the surface 

 waters have flowed thither to create these great river systems. The 

 Atlantic edge of the continent, having been squeezed upwards, was 

 eroded more and more deeply by downward-rushing watercourses; 

 ravines were eaten out, between which the remaining rocks rose like 

 towers and gigantic dice, as we can see to-day in the mountains on 

 the coast of Espirito Santo (Fig. 10) and around Rio, and in the 

 jagged outline of the Organ Mountains. Deposits of debris have 

 once more joined the islands to the mainland — as the Sugarloaf, 

 for example, has been joined, which was once completely surrounded 

 by the sea, as its less lofty sisters are to-day (Plates 5, 6, 7). 



We must think of Brazil, through all these periods, as inhabited 



by a rich fauna, which during these long ages had time to develop 



in independence. Thus, of the 131 species of mammal in South 



America, no less than 103 — that is, four-fifths — and of the 920 species 



160 



