H 



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 char- 

 acteristic Devonian fossils, corresponding more or less 

 with those of the Hamilton and Corniferous 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 Marajo, at the mouth of the Amazonas, at 

 that time only imperfectly known, and discovered large 

 quantities of richly ornamented pottery, mostly frag- 

 mentary. These have since been made the subject of 

 considerable study by Professor Hartt. The sea coast 

 was examined at several points, from Para to Pernam- 

 buco, and, in the neighborhood of the latter city, the 

 fossiliferous Cretaceous formations of the province of the 

 same name, were studied for the first time. At all of the 

 localities visited they made large collections in geology 

 and zoology, which were sent to the United States and 

 are now contained in the museum of Cornell University. 



Prof. Hartt's researches on the Amazonas did not tend 

 to bring proof of the former existence of glaciers there. 

 The Serra of Erere was found not to belong to the series 

 of table-topped hills, as Prof. Agassiz had been led to 

 suppose, but to consist of inclined strata of very irregular 

 outline. The Devonian fossils of the plain were from a 

 portion of the supposed "drift" material of Agassiz. 

 Prof. Hartt did not find time to examine any of the true 

 table-topped hills on this trip, and it was largely for the 

 purpose of doing this that he returned to the Amazonas 

 in 1870, accompanied only by Mr. O. A. Derby. 



The table-topped Serra of Parauaquara and the Serra 

 of Tauajuri, of another class, and both wholly unknown 

 to science, were visited, but gave no evidence ol having 

 been formed through the agency of glaciers. The tossil- 

 iferous localities of Erere and the Tapajos were reexam- 

 ined, and larger collections made from them. The fresh- 

 water shell heaps of Taperinha were carefully explored 

 by Prof. Hartt. and the mounds of Marajo by Mr. Derby. 



