Kathbun.] 344 [April 17, 



formations which compose much of that region. He also studied the 

 structure of the Abrolhos Islands and Reefs, which lie off' the coast of 

 Bahia, to the southeast of the town of Caravellas. The islands are of 

 stratified deposits, capped with trap, while the reefs, which had never 

 before been to any extent examined by a naturalist, are of coral, 

 generally assuming curious tower-like forms, and often growing 

 together to form a large connected expanse. 



In addition to throwing new light on the formation of certain kind« 

 of coral reefs, he also discovered a large number of species of corals, 

 of which the majority were new, but belonged to West India types. 

 The absence of many prominent West India genera, such as Madre- 

 pora, Meandrina, Diploria, etc., was noted by him. The Cretaceous 

 region of Sergipe was visited, and yielded many fossils, which have 

 been in part described by Prof. A. Hyatt. 



In the short interval which elapsed between his first and second 

 trips, he was engaged in scientific teaching and lecturing in and near 

 New York city, at the Cooper Institute, Pelham Priory, and other 

 places, where he attained much success and made many warm friends 

 who aided him in his second Brazilian expedition. In 1868, soon 

 after returning the second time, he was appointed Professor of 

 Natural History in Vassar College ; but he resigned this position in the 

 autumn of the same year to accept the chair of Geology in Cornell 

 University, where he was retained at the head of the department of 

 geology until the time of his death. In 1869 he was elected General 

 Secretary of the American Association for the Advancement of Sci- 

 ence, to serve at the meeting of 1870, but before that time he had 

 departed on his third trip to Brazil. 



While at Cornell University, when not occupied by college duties, 

 he was engaged in working up the results of his Brazilian explora- 

 tions, and in preparing his report, as geologist to the Thayer Expe- 

 dition. This report, however, grew to so large a size, and was so 

 complete in itself, that it was found advisable to publish it separately, 

 in 1870, as "The Geology and Physical Geography of Brazil." It 

 forms a large octavo volume of over six hundred pages and contains, 

 in addition to an account of his own researches, a resume of our pre- 

 vious knowledge of the natural history of the country. It is thus 

 not limited to a discussion of the subjects indicated by the title, but 

 treats of the topographical and general features of the country, of its 

 flora and fauna, both marine and terrestrial, and its mining, agricul- 

 tural, commercial, and manufacturing interests. The numerous maps 



