Note 1 — Chapter XVI · THE DESCENT OF THE RIO GY-PARANÁ

The Gy-Paraná had been descended by two parties which Colonel Rondon detached for this purpose from his main expedition of 1909. The first, under the zoologist Alipio de Mirando Ribeiro, went down the Pimentá Bueno and the Gy-Paraná to the Madeira; the second, under Lieutenant Antonio Pyrineus de Souza, descended the Jarú and the Gy-Paraná (see map). It was the reconnoissance survey made by the first party that established the fact that the Gy-Paraná, instead of flowing northwest throughout its course, as until then supposed, turns abruptly north in 11½° south latitude, and flows in this direction for nearly three degrees, until, at another abrupt bend in 9° south, it turns west and empties into the Madeira.