APPENDIX. 537 
From Januaria Mr. St. John followed the San Francisco to the 
Villa do Barra, where he made a short stay, and then resumed 
his journey by land through the valley of the Rio Grande to the 
Villa da Santa Rita, thence to Mocambo and across the table-land 
separating the basin of the Rio San Francisco from that of the Rio 
Paranahyba. At Paranagua he remained several days, and made 
a considerable collection from this vicinity. Thence he followed 
f 
the valley of the Rio Gurugueia to Manga, one hundred and twenty 
leagues from Paranagua. At Manga he embarked on one of the 
singular river-boats made of the leafstalks of the Buriti palm, and 
descended the Paranahyba to the villa of San Gon^allo. Here he 
stayed for some time to collect, and forwarded from this vicinity a 
considerable number of specimens, chiefly reptiles, birds, and insects. 
His next station was at Therezina, the capital of the province of 
Piauhy, where he made one of the most interesting collections of 
the whole journey from the waters of the Rio Poty. The Poty is a 
tributary of the Paranahyba, into which it empties below Therezina. 
In examining this collection, I was particularly struck with the gen- 
eral similarity of the fishes contained in it to those of the Amazons. 
They exhibit throughout the same kind of combination of genera 
and families, although the species are entirely distinct. Thus, from 
a zoological point of view, the basin of the Parahyba, though com- 
pletely separated from it by the ocean, would seem to belong to the 
Amazonian basin, as it unquestionably does from a geological point 
of view. The character of the drift deposits along the Rio Guru- 
gueia and the Rio Paranahyba shows" this area to have been con- 
tinuous with the basin in which the Amazonian drift was deposited ; 
and the similarity of their zoological features is but another evi- 
dence, from an entirely different source, of the extensive denudations 
which have isolated these regions from one another by removing 
the tracts which formerly made them a unit. 
From Therezina Mr. St. John proceeded to Caxias, and finally 
arrived in Maranham, by the way of the Rio Itapicurii, on the 8th 
January, 1866; having completed a journey of moie than seven 
23* 
