234 THE POPULAR SCIENCE MONTHLY. 



of his many other duties, he was soon obliged to resign that position. 

 The results of his researches may be briefly summed up as follows : 

 Before he went to Brazil on his second trip, in 1867, scarcely anything 

 was known of fossiliferous deposits there, and thus no material existed 

 toward the study of the systematic geology of the country. A few 

 Cretaceous fossils had been recorded from Bahia ; the Danish naturalist 

 Luns had very fully described the bone-caverns of Lagoa Santa in 

 Minas Geraes, and we knew of coal-plants from Rio Grande do Sul ; 

 but beyond this the paleontology of Brazil was a perfect blank. Hartt's 

 greatest achievement in Brazil was probably his solution of the struct- 

 ure of the Amazonian Valley. It was founded on the best of paleon- 

 tological evidence which proves the existence of an immense palaeo- 

 zoic basin lying between the metamorphic plateau of Guiana on the 

 north, and that of Central Brazil on the south, and through which 

 flows the river Amazonas. Silurian, Devonian, and carboniferous rocks, 

 make up the series in regular succession, and in many localities are 

 highly fossiliferous. He has explained the character of the isolated 

 Cretaceous deposits, mostly discovered by himself, existing along the 

 coast from Para, to Bahia, and of the Carboniferous and other regions 

 south of Rio. He has shown us the manner in which the rocky struct- 

 ure of Brazil w r as built up, and has done much toward solving the rela- 

 tions of the crystalline rocks which compose by far the larger portion 

 of its surface. He has explored the shell-heaps, burial-mounds, and 

 other relic-localities of the prehistoric tribes from far up the Amazonas 

 to the southernmost coast province. We owe to him also the first real 

 satisfactory explanation of the reefs of Brazil, which he distinctly 

 shows to be of two kinds sandstone and coral. He spent much time 

 in studying the customs and languages of the modern Indian tribes of 

 the Amazonas and Bahia, and collected very much material toward a 

 grammar and dictionary of the Tupe Indian language in several of its 

 dialects. But to attempt a complete account of Prof. Hartt's Brazilian 

 explorations and discoveries would require a longer article than we can 

 give here. In connection with the Geological Commission of Brazil he 

 founded a large museum in Rio de Janeiro, which w T ill always bear tes- 

 timony to his great final undertaking. His field-parties made very ex- 

 tensive collections of rock-specimens and fossils, and in the explora- 

 tions of the reefs they gathered a large collection of marine inver- 

 tebrate animals of all kinds. About a year ago, when the members of 

 his survey were mostly recalled to Rio for the purpose of writing up 

 their reports and of studying the material they had collected, it was 

 found that some six hundred cases had been sent in from the field, and 

 were awaiting suitable quarters. A large building was obtained, and 

 in the course of several months there appeared a museum of geology 

 and marine zoology that would have done credit to a much larger com- 

 mission working a much longer time. It contained fossils, minerals, 

 and rocks, from nearly every known geological locality in Brazil, and 



