REVIEWS 271 



study an equal understanding of stratigraphic and structural problems 

 or has pursued the investigation so persistently as has Dr. Branner him- 

 self. 



In his foreword the author states: 



The accumulation of the data for the geologic map of Brazil was begun by 

 me in 1874, when I first went to that country, and has been kept up as oppor- 

 tunities offered, down to the present time. The gathering and study of the 

 material and the preparation of the map may therefore be said to represent the 

 work of a considerable portion of a hfetime. 



In addition to the large amount of information secured through his 

 own personal observation the author has utilized the work of his several 

 assistants, who have accompanied him on his expeditions to Brazil, and 

 he has availed himself of every scrap of published or unpublished data 

 which could stand the rigid scrutiny to which he subjected it. His 

 resources in every direction have been unusual, but what stamps the 

 map with authority is the character of its author, whose life-work in 

 Brazil it epitomizes. 



The geologic facts recorded in the map and accompanying text will 

 serve three classes of students. Those who are interested in the history 

 of Brazil as an example of the geological development of a great conti- 

 nental nucleus will find in the summary comprised under "Outlines of 

 Stratigraphic Geology," pp. 202-23, ^ brief but comprehensive state- 

 ment. Those students who may be interested in the geology of indi- 

 vidual states or in local details will turn to the general geology described 

 by states in alphabetical order, and to the bibliography which fol- 

 lows the statement regarding each state; and those who are chiefly 

 interested in the economic resources will find valuable notes also under 

 the separate articles regarding individual states. 



Branner's text is in itself a summary. As may be seen by reference 

 to the extensive bibliographies accompanying the descriptions of the 

 several states, a full discussion would constitute a large volume. In 

 order, however, to indicate the general facts of the geology in bare out- 

 line the summary may be summarized as follows: 



The Brazilian complex, or basement, of the Brazilian plateau of 

 South America is a mass of crystalline metamorphic and eruptive rocks, 

 granites, gneisses, and schists, which closely resembles the Archean 

 complex of the Canadian shield. They constitute the surface in the 

 eastern mountain ranges and plateaus, forming a broad belt all along the 

 Atlantic Coast, except in the far south. They occur both north and 

 south of the geosyncline of the Amazon Valley, and outcrop at numerous 



