442 Lisboa — Permian Geology of Northern Brazil. 



Dr. G. A. Waring and Dr. Manoel Arrojado Lisboa in their 

 trip in the northwest across the Serra Grande, descending into 

 the Poty valley noticed a disturbance of the sediments and the 

 occurrence of diabasic rocks. For this reason they supposed, 

 even before they knew of this work, that the sediments of the 

 channel of the Poty river were pre-Cretaceous. 



Thus a great part of the sediments of the state of Piauhy 

 certainly belong to the Parnahyba series, while the Cretaceous 

 area, which has hitherto been considered as embracing almost 

 the whole state, is greatly restricted. 



Very likely the sediments of this series, which we know con- 

 tinues to the lowlands of the Tocantins, extends to the mouth of 

 the Araguaya, and probably embraces the slopes of the chapa- 

 das where the Gurupy and Guama rivers rise. 



In his trip to the Tocantins the author frequently found, 

 above Alcobaca, beds of flints in red sandstones which permit 

 the presumption that sediments of the Mearim series occur in 

 the plateaus of the region. 



Conclusion. — It is too early to correlate the sediments of the 

 Maranhao system with those of Santa Catharina. 



The lithologic similarity of the sediments of the different 

 series of the north and of the south of Brazil is very notable, 

 especially that of the beds of Pastos-Bons, of the top of the 

 Parnahyba series with those of Estrada Nova, and of the series 

 of Mearim with that of S. Bento. 



The author recognizes that they occur with the same aspect 

 in the base of the plateaus of Matto Grosso, in the Aquidauana 

 and Miranda valleys, in the basin of the Paraguay, while the 

 existence in the north of the bituminous shales almost certainly 

 in the upper part of the Permian under conditions that recall 

 the bituminous shales of Iraty in the south is worthy of note. 



It is clear that the zone or area of upper Paleozoic sediments 

 in northern and central Brazil is much greater than has been 

 heretofore supposed. 



The study of the recognized Permian in Brazil and of its 

 abundant fossils of different types of Psaro?iius, is of great 

 interest and offers a great field for observations. 



It would be of still greater interest if the lower Permian 

 series corresponding to the Tubarao series in Santa Catharina 

 could be recognized. 



In the channel of the Parnahyba below Nova-York the rec- 

 ognized Permian sediments occur at the horizon of Psaronius 

 or in a higher horizon. Also the slopes of the Maranhao pla- 

 teau which drain toward the lowlands of the Tocantins consist 

 of the same sediment containing these fossil plants. 



In the lowlands of the Tocantins, between Carolina and 

 Porte Nacional, the Permian rock encountered is also the sand- 

 stone from the same horizon as Psaronius. 



