REVIEWS. 
The Unpublished Papers of the Geological Survey of Brazil. (Fra- 
balhos restantes ineditos da Commissio Geologica do Brazil.) 
Boletim do Musen Paraense, Vol. II, No. 2. Oct. 1897, 
pp. 155-204. 
At the suggestion of Professor O. A. Derby, now chief of the State 
Geological Survey of Sao Paulo, the Para Natural History Museum 
(Museu Paraense) has undertaken to publish the unpublished papers 
of the defunct Geological Survey of Brazil relating to the geology and 
physical geography of the lower Amazon. The October number of the 
Boletim contains the first installment of these papers. The parts thus 
published consist of an “Introduction,” “The Breves Region,” and 
“The Rio Tocantins” by Ch. Fred. Hartt, and of “The Island of 
Marajo” and a “ Reconnaissance of the Rio Maecurti” by O. A. Derby. 
These are to be followed later by other chapters on “‘ Rio Trombetas” 
by Derby, on “ Paracary” by Herbert H. Smith, and on the “Tajury,” 
“Paranaquara,” “Serra da Maxira,” and “Monte Alegre and Ereré” 
by Hartt. 
These papers represent work done by the extinct Commissao Geo- 
logia do Brazil from 1875 to 1878, and it might be supposed that it is 
now too late to publish them, especially as the Museu Paraense has 
lately begun active work in the same region. But it should be remem- 
bered that the State of Para, occupying the whole of the Lower Ama- 
zon, covers an area of 443,900 square miles—nearly twice that of the 
state of Texas—and that the difficulties of exploration in the dense 
and trackless forests that cover that sparsely inhabited region are 
almost or quite beyond the comprehension of those who have not 
encountered them. 
As Hartt well says, when he entered the Amazon valley for the first 
time in 1870, it was, geologically, a ¢erra incognita. Since that time 
and as the result of the tireless efforts of Hartt and Derby a vast 
amount of important information has been gathered and published 
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