18 ANNALS NEW YORK ACADEMY OF SCIENCES 



waterfalls of Forto tie Principe da Beira. They were also seen along Eio 

 Mamore above Guaja Mirim, where the Serra de Pacas Novas approaches 

 the river. Evans has reported gneisses, etc., from the Eio Beni and the 

 Madeira falls. Katzer has maintained that this same basal highland for- 

 mation extends under the deep alluvial deposits of the lower Amazon 

 Valley. As a result of the writer's own observations, he is convinced that 

 this is in the main the correct view. Hence this basal highland formation 

 is very large, perhaps larger than indicated on Plate III. 5 The extent 

 and form of these ancient rocks have given South America its present 

 shape from the very beginning. 



Silurian 6 



Silurian fossils have been reported from Eios Curua, Maecuru and 

 Trombetas, which are affluents from the north side of the lower Amazon 

 Eiver; from Bom Jesus da Lapa, of Bahia; from some of the promon- 

 tories of Venezuela; from the eastern chains of the mountains near the 

 headwaters of Eio Bermejo, Argentina; west of San Juan along the 

 eastern base of the Andes of northwestern Argentina; from Sierras de 

 Famatina and La Eioja ; from the mountains on either side of Sierra de 

 Aconquija; from Sierra Aguilar, and from Cuzco, in southern Peru, ex- 

 tending past Illampu and Illimani through western Bolivia toward the 

 Argentine chains of mountains. (?) Silurian (Artlirophycus liarlani) 

 was reported from Sierra de la Tandil. 



The locations of these formations are shown on Plate IV, except "that 

 no distinction has been made for Ordovician because of the lack of data. 



Devonian 



Devonian fossils have been reported from Alameirim to Eio Uatuma at 

 Erere, Eio Maecuru south of Larangal on the south side of Eio Amazonas ; 

 from Lagoinha near Cuyaba; from a belt extending from the State of 

 Sao Paulo into the State of Parana at Ponto Grosso, at Jaguarahyva and 

 in the Ivahy basin ; in southern Peru and about Lake Titicaca, and in the 

 Andes of Chili. Doubtfully from the northern part of Sierra TandiL 

 The locations of these formations are shown on Plate V. 



Carboniferous 



Carboniferous fossils have been reported from Eios Trombetas, Curua., 

 Maecuru, Uatuma to Janary near Prainha and at Alemquer on the north 



6 It must be granted that the regions supposed to yield exposures of Archean rocks may 

 with more careful study he materially diminished, as has been the case in North America 

 and Europe. If these rocks mapped as Archean are all older than the Carboniferous 

 formations, then the ensuing views are not in the least affected. 



6 The Cambrian has not been mapped because of the lack of data. Deposits of this age 

 have only been reported from a few places, as northern Argentina by Keyser, etc. 



