GEOLOGY OF THE LOWER AMAZON REGION^ 



CHARLES SCHUCHERT 



Dr. Katzer has shown remarkable abihty in writing local geologi- 

 cal treatises of a comprehensive nature. His largest and best work 

 is The Geology of Bohemia; and the smallest, The Geology of Bosnia. 

 The present admirable memoir under review is the third one of his 

 local summaries. All are written in the German language. 



Much of Dr. Katzer's knowledge of the geology of Brazil (more 

 especially of Para) was obtained during the seven years he was state 

 geologist and stationed in the Museu Paraense ; yet it is quite evident 

 that he is also familiar with the literature, in many languages, treating 

 of the geology of South America. 



The present article chiefly calls attention to the general geological 

 sequence in the lower Amazon region. Those desiring further 

 information must consult the Grundziige itself. 



The succeeding pages give, in the language of the reviewer, a con- 

 densation of the chapter entitled, "The Geological Development of 

 the Lower Amazon Region" (pp. 237-62). Following this statement, 

 the present writer will take up the Paleozoic formations in more detail, 

 especially those of the Devonic. 



PART I. KA.TZER'S SUMMARY OF AMAZONIAN PALEO- 

 GEOGRAPHY 



Katzer states that the general observation, that the present rela- 

 tion of the Atlantic Ocean to Brazil was the same in the older geologi- 

 cal epochs — i. e., that the old oceans spread upon the land from the 

 east — is not supported by the facts. 



The distribution of the Archean shows that in the north and east 

 occur the oldest rocks of the lower Amazon region. Upon these 

 rest fresh-water deposits of Tertiary and Quaternary age. The 



I This paper is largely based on Friederich Katzer's Grundziige der Geologie des 

 unteren Amazonasgebietes {des Staates Para in Brasilien) (Leipzig, 1903; pp. 298, a 

 geological map, numerous text-figures, and 16 plates of fossils; 8vo). The writings 

 of Hartt, Rathbun, Derby, and Clarke have also been liberally' drawn on. 



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