FISHES OF CEARA, BRAZIL JORDAN AND BRANNER 7 



of these inland sediments, however. What is here given has been 

 collected from the notes of Spix and Martins and of Gardner. 



While the structural relations of these highland beds is not cer- 

 tainly known at present, such information as we have suggests the 

 relations indicated by the accompanying theoretic section across 

 northeastern Brazil, say from about Maranhao on the north to 

 Sergipe on the south, and passing through the Serra do Araripe. It 

 should be added, however, that the slates reported near Lavras in 

 Ceara are probably Paleozoic. No attempt is made to represent 

 those slates in this section. There are probably local variations in 

 the dips and relations of the Cretaceous beds which are not sug- 

 gested in this hypothetical section. 



Barao de Capanema says that the beds of the Serra da Ibiapaba 

 along the northwestern boundary of Ceara dip toward the west, and 

 he appears to think that the rocks of that range are the same as those 

 of the Serra do Araripe. This attempted correlation is not based 

 upon paleontologic evidence, and may be altogether erroneous. 



The table-lands so characteristic of the Serra do Araripe follow 

 the water-sheds toward the south and west. Mr. J. W. Wells de- 

 scribes what seems to be a similar topography and similar rocks 

 about the southern ends of the states of Piauhy and Maranhao.^ It 

 is not to be inferred, however, that these sediments form the Serra 

 \'ermelha and Serra Dois Irmaos in the intermediate region, for the 

 notes of Spix and Martins show that where they crossed the Serra 

 Dois Irmaos the rocks are granites and schists," a fact that lends 

 support to the theory that this region was an archipelago during 

 Cretaceous time. 



The junior author's acquaintance with the geology of the sur- 

 rounding region and the few published notes of travelers suggest 

 that this northeast corner of Brazil was an archipelago at the time 

 of the deposition of these Cretaceous sediments, and that the mechan- 

 ical portions of these sediments were derived from islands of gran- 

 ites, gneisses, and schists. 



Bibliography 



J. B. VON Spix imd C. F. P. von Martius : Reise in Brasilien, 1817-1820, 11, 



799; Atlas, pi. 22, fig-. 5; iNIunchen, 1828. 

 George Gardner: On the geology and fossil fishes of North Brazil. Rep. Brit. 



Assoc. Adv. Sci. for 1840, Transactions, 1 18-120. London, 1841. Abstract 



L'Institut. 9^ Annee, No. 586, i.\, 173-174. Paris, 1841. 



^ James \V. Wells : Exploring and traveling three thousand miles through 

 Brazil. London, 1886, 11, 144. 

 ' Reise in Brasilien, 11, 768. 



