212 JOHN C. BRANNER 



published at Rio in 1887; John M. Clarke's Trilobites of the Ercre 

 and Maecuru Sandstones, Rio, 1896; Upper Silurian Fauna of Rio 

 Trombctas, Rio, 1899; Devonian Mollusks of the State of Para, Rio, 

 1899; and Devonian Fossils of Parana, Rio, 1913. Besides these 

 excellent works there are many smaller papers on paleontology 

 that cannot be mentioned here, and there still remains unpublished 

 an important volume by D. S. Jordan on the Cretaceous fossil 

 fishes of Ceara. 



During the last eight years Derby gave much of his time to the 

 study of Psaronius and its relationships. The last of his published 

 papers was on the stem structure of Tietea singularis, and appeared , 

 in the American Journal of Science for March, 1915, pp. 251-60. 



Because he had to undertake work in regions but poorly supplied 

 with maps, one of his first and most important duties, when he 

 became state geologist of Sao Paulo, was the inauguration of topo- 

 graphic work. This work was intrusted to Horace E. Williams, 

 an able and energetic young American to whom the state of Sao 

 Paulo and the scientific world are indebted for an excellent series 

 of topographic maps on a scale of one to 100,000, to say nothing 

 of his explorations of the western portions of Sao Paulo, his work 

 on the Serra da Canastra, etc. 



Derby's own list of publications on the geology of Brazil num- 

 bers 125 papers. Naturally they embrace a wide range of sub- 

 jects. Ten of his papers relate to the geology and genesis of the 

 Brazilian diamonds. One of these, on the geology of the diamond 

 and carbonado region of the state of Bahia, was the first publication 

 to give an idea of the geology of that little-known district. 



He became interested in the early cartography of Brazil, and 

 published a number of papers on that subject. 



As an author and as a scientific reasoner he was an extremely 

 cautious man, so much so that the word ''hedge 1 ' was constantly 

 on his lips both for his own guidance and as a warning to his 

 assistants. 



The last evening I spent in his rooms at Rio de Janeiro he 

 referred to this personal trait, and remarked that it had prevented 

 his marrying — that he was too cautious to take the risk. This 

 cautiousness of his was probably the real reason for some of the 



