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When the National Museum of Rio de Janeiro was 

 remodeled, in 1876, the Minister of Agriculture, having- 

 the matter in charge, solicited Prof. Hartt's assistance, 

 and, at the same time, made him director of the depart- 

 ment of Geology ; but his many other duties soon forced 

 him to relinquish the new task. 



Prof. Hartt's plan of operations was to first make a 

 preliminary reconnaissance of all the accessible portions 

 of the Empire, before entering much into detail work; 

 but, as will be seen in the sequel, he succeeded in very 

 thoroughly investigating some of the regions he explored. 

 The following general account of the explorations of the 

 Brazilian Survey is based in part upon some of Prof. 

 Hartt's unpublished reports. Regarding the character 

 of the work, Prof. Hartt states in one of his late reports to 

 the Minister: "As is the duty of every scientific man, I 

 have carried on my investigations in a purely scientific 

 way, hoping that later on they would not fail to be of 

 practical importance." While awaiting instructions, 

 Hartt visited the gold regions of Sjio Gongalo and Cam- 

 panha. An account of the results of this trip was pub- 

 lished in the American Journal of Science and Arts for 

 June, 1876. 



The active work of the Commission began in June, 

 1875. They explored the Cretaceous deposits near the 

 coast, from Pernambuco to Parahyba do Norte, taking 

 Maria Farinha, where Cretaceous fossils were found in 

 1870, as a basis. This formation was found to be very 

 extensive and richly fossiliferous. With the marine fos- 

 sils of Maria Farinha were discovered the remains of a 

 large species of crocodile; at Iguarissii were found beds 

 with fish teeth, mostly sharks, and also some reptilian 

 teeth. To the west of the Cretaceous, and not far from 

 the coast, is the gneiss zone. The coast southward to 

 Cape St. Agostinho, Rio Formoso, the island of Sto. 

 Aleixo, and the Rio Sao Francisco, to, and including, the 

 beautiful falls of Paulo Affonso, were all examined, and 

 on the latter river fossils were discovered in the Creta- 

 ceous formation. Extensive studies were made on the 

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