Lisboa — Permian Geology of Northern Brazil. 443 



This seems to indicate that these sediments of the upper 

 Permian outcrop in the states of Maranhao, Piauhy, and Goyaz 

 sufficiently thick and sufficiently flat to permit the excavations 

 of the river valleys in them. 



It is important to recognize that the upper Permian sedi- 

 ments with Psaronius in the north of Brazil are approximately 

 horizontal from their limits, undoubtedly recognized from the 

 parallel of Campo Maior north of Therezina to the channel of 

 the upper Tocantins in the center of the Brazilian plateau. 



In southern Brazil the coal measures are about 150 feet 

 below the Iraty shale, which is the lower limit of the sediments 

 with Psaronius, but for the time being we can foretell nothing 

 as to the conditions and occurrence of the lower Permian in 

 the north of Brazil. 



North of Campo Maior some wells were dug in the Permian 

 beds, and in one of these a bed of pyritous lignite was found 

 which I myself have not had an opportunity to examine. This 

 indicates the probable presence of older sediments than those 

 of the upper Permian with Psaronius. 



In Goyaz, in the bed of the Tocantins between Porto JSTacional 

 and Carolina, the Archean terrane with lower Paleozoic erup- 

 tive outcrops. There it may be possible to recognize the basal 

 sediments of the Permian in northern Brazil. 



It is now clear that the continent of Gondowana embraced a 

 large part of both northern and southern Brazil, nearly from 

 the Atlantic directly below the mouth of the Amazon, to the 

 boundary with Uruguay and even beyond it. 



In 1909 1 had occasion to call the attention of the Geolog- 

 ical Service of Brazil to the occurrence of certain fossil plants 

 found by the Brazilian engineer Nascimento Moura in a well 

 dug near Aracy, in the semi-arid part of the state of Bahia. 

 In April, 191^, I sent specimens of these plants to Professor 

 R. Zeiller of Paris, who recognized the genus Alethojoteris, an 

 upper Carboniferous or Permian form. Later, David White 

 made a study of specimens of these plants collected at the same 

 place by Dr. J. C. Branner in 1911 and fully confirmed the 

 determination of Zeiller. He named the species Alethopteris 

 brannerir It is thus clear, that the Permian covers not only 

 parts of Goyaz, but of Bahia between the Rio S. Francisco and 

 the coast. 



Recalling trips made in the upper Rio S. Francisco regions 

 in Minas, in the Rio Paracatu basin, and in the basins of upper 

 tributaries of the S. Francisco, I think it probable that certain 

 sedimentary beds of that region may hereafter also be found 

 to be of Permian age. 



Rio de Janeiro, Brazil. 



*This Journal, xxxv, 615, June, 1913. 



