BRANNER: THE STONE REEFS OF BRAZIL. 9 
Palaeozoic." They might with just as much propriety, however, be re- 
ferred to the Jurassic or Triassic. So far as the present discussion is 
concerned, the age of these pre-Cretaceous beds is a matter of but little 
importance. Our present interest is chiefly with the Cretaceous and 
with the post-Cretaceous history. 
The Cretaceous. — There are marine Cretaceous beds in the State of 
Sergipe resting upon the Palacozoic and crystalline rocks of the interior, 
but how far north and south these beds extend is not known at present. 
It is quite possible that a narrow strip of Cretaceous rocks extends up 
and down the coast for a long distance, and it is possible, too, that the 
bottom part of the series here set down as Eocene is really Cretaceous. 
What is the age of the Bahia beds? — There has been some confusion 
in the classification of the Cretaceous and Tertiary beds of the east coast 
of Brazil. It ig necessary, therefore, to bring together the evidence 
upon which the classification 18 based, and to ascertain, if possible, which 
beds are Cretaceous and which Tertiary. Without entering into de- 
tails it may be accepted as satisfactorily proved that the highly fossilif- 
erous beds of the Sergipe basin are Cretaceous. The fossils from these 
beds are described by Dr. C. A. White in his excellent monograph.? 
Some of the other beds, however, have been referred to both Cretaceous 
and Tertiary. Inasmuch ав the rocks of the Bahia sedimentary basin 
have yielded more palaeontologic evidence than any one locality outside 
of Sergipe, the age of the beds of that region will be considered first and 
in more detail. It is with these that we now have to deal. 
The earliest paper in which a definite geologic age is assigned the 
coast sediments is one by J. Е. М. Von Olfers, published in “ Karsten’s 
Archiv fitr Mineralogie, eto.” ТУ. 173-180, at Berlin in 1832 under the 
title, “ Ueber das niedrige Felsenriff der Küste von Brasilien.” In this 
paper the author puts down as Tertiary the stone reefs, the sandstones 
of the Amazon valley, the rocks of the Bahia basin, 
mentary beds from Maranhäo to the Abrolhos. He makes no mention, 
however, of any palaeontologic evidence of the ages of any of these rocks, 
Tn 1836 Charles Darwin touched at Bahia, and though he does not 
give their names, he speaks of having found Tertiary fossils at the head 
of the Вау, 
and all the sedi- 
1 J. C. Branner, the Cretaceous and Tertiary geology of the Sergipe-Alagóas 
Basin. Trans, Amer. Phil. Soc., XVI., p. 881-882, Philadelphia, 1889, 
2 Archivos do Museu Nacional, VII. Rio de Janeiro, 1887. 
3 Charles Darwin, Geological observations, 2 ed, London, 1876, p. 193, foot- 
note, 
