Professor Ch. Fred. TIartf, 31. A. — Slinonds. 83 
seuiu at Eio, but the burden was too great, and, in a short 
time he was obliged to relinquish it. 
His tirst preliminary report, as chief of the geological 
survey of Brazil — translated from the Portugese by professor 
Theo. B. Comstock — was published in the Anierican Journal 
of Science for June 1876 (III, xi, pp. 466-472). It deals with 
a variety of subjects: brief observations on the localities he 
had visited in person; the work of his assistants, Messrs. Or- 
ville A. Derby, Richard Rathbun, John C. Branner, Dr. Elias 
P. Jordao and Senhor Marc Ferrez, his photographer ; the 
kind and extent of the collections made ; and future plans. 
From it I condense the following: While awaiting instruc- 
tions, in company with commander E. P. Wilson, he visited 
the gold district in the southwestern part of the province of 
Minas Geraes and verified the occurrence of the precious metal 
in three distinct deposits, viz., — distributed in more or less 
irregular veins in Arcluean gneiss which is very much de- 
composed; in the lower part of a red earth which covers this 
region; and in alluvial deposits of the river valleys. 
In July of that year (1875) he established a laboratory at 
Pernambuco and began a systematic exploration of the vicin- 
ity which resulted in the discovery of highly fossiliferous 
beds of Cretaceous limestone. At the same time he carefully 
examined the reefs along the coast, which are of two distinct 
types, coral or calcareous and consolidated sand beaches or 
siliceous, and partly mapped the reef of Pernambuco, a rep- 
resentative of the latter class. On the following September 
he conducted a reconaissance along the Sao Francisco river 
to a point a little above the rapids of Paulo Ati'onso, which 
was supplemented by a trip to Serra de Maria Fariiiha, from 
the summit of which he was able to form a conception of the 
topography of the adjacent country — a large part of the 
provinces of Sergipe and Alagoas, and portions of those of 
Bahia and Pernambuco. He recognized a plateau of gneiss 
less than a thousand feet high, on which the rivers run in 
shallow channels, and from which peaks or serras (serrated 
ridges) rise abruptly, rarely exceeding 2,500 feet in altitude. 
In Sergipe and Pernambuco they are usually of ^-neiss or re- 
lated rocks, while in the provinces of Bahia and Pernambuco, 
in the region of the Sao Francisco river, there are large serras 
