10 ANNALS NEW YORK ACADEMY OF SCIENCES 



Introduction 



South America has not lacked the labor of scientific explorers; none 

 the less one may safely state that fully one half its surface is still prac- 

 tically unknown. This is due to the fact that its investigators have been 

 relatively few, but even had there been many scores of them they could 

 not adequately have explored such an expanse of land beset with count- 

 less natural obstacles - 



When attention is drawn to the fact that Brazil, which is one of the 

 best known South American republics, is larger than the United States 

 itself, it becomes evident that the few dozens of explorers within recent 

 times could not have examined more than the regions accessible from 

 the coast, from the few railroads and from the larger rivers. 



Pioneer work in the interior of tropical America must often depend on 

 meager and often incorrect information. This is reflected even in the 

 maps of South America, for in every one some of the material has been 

 taken from untrustworthy local sources. 



It was on account of this lack of decisive knowledge concerning cer- 

 tain parts of South America, even in the best books of reference, that the 

 director of the Carnegie Museum dispatched the writer, in 1907, in 

 charge of the Carnegie Museum Expedition to Brazil. One of the 

 primary objects of this journey was to study the distribution of the 

 fishes; but kindred problems were not to be neglected, and data were 

 collected on every hand and over a far greater territory, partially known 

 or quite unexplored, than had been originally suggested. This was found 

 possible because the writer was fortunate in maintaining excellent health 

 throughout his journeys. (See Plate II for routes followed.) 



For this excellent opportunity to explore many regions of South Amer- 

 ica, I am deeply indebted to the founder and the trustees and to Dr. 

 AV. J. Holland, the director of the Carnegie Museum. 



Acknowledgment should be made to Dr. 0. A. Derby, the director of 

 the Brazilian Geological Survey, for many favors and much useful in- 

 formation in furtherance of my work; to Prof. J. C. Branner and to 

 Mr. E. Crandall, both of whom assisted me notably on my first trip to 

 Bahia. Mr. Crandall examined my notes and map of the Cretaceous 

 •of northern Brazil. This enabled me to add valuable corrections. He 

 has also kindly submitted me some notes on the trend lines of northeast- 

 ern Brazil. Dr. Schuchert has put me into his debt for many invaluable 

 suggestions, and so too has Dr. David White for corrections and sug- 

 gestions in the discussion of the Gondwana flora. 



Mv thanks are also due to the directors and staffs of the museums at 



