438 Lisboa — Permian Geology of Northern Brazil. 



and certain calcareous, sandy, and marly beds in the middle 

 parts of Rio Itapicuru and Rio Mearim, and in the lowlands 

 of northern Goyaz. 



These bituminous shales are associated with limestones on 

 the Itapicuru river, near Oodo, on the Rio do Inferno, in 

 Igarape Santa Anna (Fazenda Uniao), in Igarape do Codo- 

 sinho, and on the Mearim river at the city of Barra do Corda. 

 A single specimen of a coniferous plant from Fazenda Uniao 

 does not fix the age of these sediments, which present much 

 the same features in all of their outcrops. 



Bituminous shales of Codb. — The bituminous shale of 

 Codo has been known since the exploration for the telegraph 

 line from Capanema. The log of a well eight meters deep on 

 the Uniao estate, river Sant' Anna, shows from top to bottom 

 the following beds : 



Log of a well at Fazenda Uniao. 



6 • laminated sandstone 



0*1 limestone 



- l shale 



- 5 . limestone 



0-2 black shale 



0*2 limestone 



l cm bituminous shale continues in depth. 



It dips about 12° to the north. 



In the Igarape do Codosinho, the total thickness of the cal- 

 careous, bituminous sediments is six meters. They overlie a 

 white, soft, coarse-grained, loosely consolidated sandstone. The 

 occurrence at Ribeirao do Inferno is the most interesting. 



At Igarape do Inferno the sediments dip about 30° to the 

 south and strike east and west. I have measured a thickness 

 of twenty centimeters ; the total thickness is probably more 

 than fifty centimeters. 



The lower sediment is a boghead coal, similar in appearance 

 to the Marahu. shale of Bahia. It overlies a thick bed of well 

 laminated bituminous shale made up of distinct materials ; 

 black bands with intercalations of a bituminous material, com- 

 posed of shiny grains, resin-colored and rounded, in the midst 

 of an ashy gray to dark gray mass apparently formed of the 

 same material as the shales. This material has not yet been 

 studied. 



In the bed of the Mearim river the bituminous shales are 

 also covered by a limestone, with gypsiferous intercalations 

 and siliceous beds parallel to the bedding, which dips to the 

 south. A flaggy sandstone overlies the limestone with a thick- 

 ness of more than fifty meters. A conglomeritic flint (?) bed 



