730 CHARLES SCHUCHERT 



vicic. Then follow faunas comparable with those of the American 

 Clinton and the higher Niagaran formations. 



DEVONIC SYSTEM 



The Devonic of the state of Para consists of marine littoral deposits. 

 All the fossil locahties are to the north of the Amazon. 



The most complete development of the Devonic is that of the 

 valley of the Rio Maecuru. Here, according to Katzer (p. 191), the 

 sequence is the following (zones 2 and 3 are referred by the present 

 writer to the Erere formation of Derby, and 4, 5, and 6 to the Mae- 

 curu of Derby) : 



Upper Carbonic. 



Unconformity. 



1. Black, in part thin-layered shales, with lenticular beds of sand- 

 stone and very large concretions of highly bituminous blue-black 

 limestone. Toward the top the beds are rich in pyrite. Thickness 

 not determined, but considerable. The only known fossils are 

 Spirophyton and Nuculites ererensis. Curua formation of Derby. 



2. A series of reddish, micaceous, sandy shales or shaly sandstones. 

 Thickness not given. The only fossils are Spirifer pedroanus, Cama- 

 rotoechia dotis, and Tentaculites eldredgianus. 



3. Dark-gray or blackish, rough-layered sandstone, without 

 fossils. Thickness, lo"". 



4. Hornstone. Thickness, 10™. 



5. Sandstone full of fossils. It is from this horizon that most of 

 the fossils of the Rio Maecuru are derived. (See faunal Hst. ) Thick- 

 ness not given, but on the Rio Curua, about lo"' thick. 



6. Thin-layered sandstones interspersed with shales. Thickness 

 not given, but probably about lo"' to 15™. 



Siluric sandstones. 



West of the Rio Maecuru (about 25 miles), on the Rio Curua, the 

 entire thickness of the Devonic is about 50™, and the system seems 

 to rest comformably upon the Siluric. The development in both 

 places is analogous. 



To the east of the Rio Maecuru (about 75 miles) there is another 

 good exposure of the Devonic in the bays of the Campo of Erere. 

 The exposures indicate a thickness of about 75™. In many places 



