GENERAL AND ECONOMIC GEOLOGY 307 



the places mentioned by him. The notes of Sellow and of other geolo- 

 gists give the impression that the region of granites and gneisses south 

 of the trap escarpment contain many infolded or infaulted patches of 

 Permian or other older rocks. With the data now available it is quite 

 impossible to outline these areas. 



The paper of Dr. K. Walther, of Montevideo, "Ueber Transgressionen 

 du oberen Gondwana-Formation in Siidbrasilien u Uruguay/' deals with 

 the geologic history of the State of Rio Grande do Sul and is altogether 

 one of the best papers on the geology of that state. 



On the geological map the coastal deposits in Rio Grande do Sul are 

 put down as Quaternary. It is highly probable that some of these de- 

 posits are Pliocene, but thus far the paleontologic evidence of their Plio- 

 cene age is lacking. 



The chief publications on the coal of the state are those of Bem, 

 Cabral, Dahne, Frank, Ginty, Graga, Hull, Lange, Lyon, Parigot, Plant, 

 Pederneiras, Primavera, Thornton, and I. C. White. 



Papers on the gold and copper deposits are those of Eddy, Gorceix, 

 Groddeck, Netto, and Walther. 



The principal authors who have written on the paleontology of the 

 state are Carruthers, Seward, White (David), Woodward, and Zeiller. 



General geology. — Tertiary and Quaternary sediments, inclosing Lagoa 

 dos Patos and Lagoa Merim, form a belt along the coast and lap back 

 against the Archean area. To the landward of this belt lies an area of 

 Archean rocks with here and there outliers of Triassic rocks, and of 

 Lower Permian rocks, in which coal is found. The high land in the 

 northern and western parts of the state is mostly pre-Cretaceous trap 

 resting directly on Triassic beds. 



These geologic divisions correspond fairly well with the broad topo- 

 graphic features of th^ state. The Archean rocks are charactiristic gran- 

 ites, gneisses, and schists. There are probably some of the older Paleo- 

 zoic rocks within the Archean area, but they have never been located in 

 detail. 



The oldest rocks in the state from which fossils have been obtained 

 are the Lower Permian in which the coal occurs. The rocks of this series 

 are sandstone, shales, and coal beds, all of them somewhat folded. 



The Triassic beds are reddish sandstone, approximately horizontal, but 

 broken by many faults, some of them having considerable dislocations. 

 The discovery in these beds of reptilian bones (Scaphonyx fischeri) near 

 Santa Maria da Bocca do Monte, in Rio Grande do Sul, made it possible 

 for Dr. A. Smith Woodward to determine their age satisfactorily. 



The eruptive rocks that overlie the Triassic in Rio Grande do Sul are 



