Kathbun.] 346 [April 17, 



The above general account suffices to show how little was known 

 of the systematic geology of Brazil, at the time when Hartt had fin- 

 ished his second trip to that country. 



In the year 1870, the same in which his book was issued, Prof. 

 Hartt organized the largest of his own expeditions from the United 

 States. It was composed, besides himself, of Prof. Prentice and eleven 

 students of Cornell University. His object in taking so many young 

 men into a new field was to give them thorough practical training, 

 and to stimulate them to undertake original work. He says, in his 

 report of this expedition, that he did not expect to make scientists 

 of them all, but hoped that some might be thus induced to accept 

 that calling. Of that band of students, he refers to four (O. A. 

 Derby, T. B. Comstock, H. H. Smith, and TV. S. Barnard), who are 

 to-day doing scientific work of a high character. The means for 

 defraying the expenses of the trip were contributed by several par- 

 ties, most prominent, of whom was Mr. E. B. Morgan of Aurora, 

 N. Y., whose name has been given to this and the subsequent expe- 

 dition. 



Not having been successful in his former trips along the coast, in 

 finding other fossiliferous deposits than the Cretaceous, Prof. Hartt 

 determined to change his field of research, and explore the Amazonas. 

 Accordingly, he went with his party directly to Para, and in the 

 neighborhood of this city spent some time in training his inexperi- 

 enced assistants. The tributary rivers, Tocantins, Xingii, and Tapa- 

 jos, were then examined throughout their lower courses, and many 

 valuable geological facts ascertained. On the Tapajos were discov- 

 ered the highly fossiliferous Carboniferous deposits from which, as 

 already mentioned, Major Coutinho had before obtained some unde- 

 termined fossils. 



At the falls on each of the above named rivers were found series of 

 metamorphic rocks, which have been referred, from their position and 

 lithological characters, to the Silurian. Passing to the north of the 

 Amazonas, they minutely investigated the geology of the vicinity of 

 Monte Alegre and the Serra of Erere. On the plain of Erere were 

 discovered sandstones and shales with characteristic Devonian fossils, 

 corresponding more or less with those of the Hamilton and Cornife- 

 rous groups of New York State. These were the first Devonian 

 fossils found east of the Andes in South America. 



One of the party examined the ancient Indian mounds of the 

 island of Marajd, at the mouth of the Amazonas, at that time only 



