The Amazon Main River is navigable for ocean steamers as far as Iquitos, 2300 m.
Steamer " Wilmington " ascended it to Iquitos in 1899.
Taking four roughly equidistant places, the rise at Iquitos is 20 ft., at Teffe 45, near Obidos 35, and at Path 12 ft.
Path, Manaos and Iquitos are now thriving commercial centres.
The principal tribes are the Quijos or Canelos, who are settled about the headwaters of the Napo, on the eastern slopes of the Andes, and are in great part grouped about the missions; the Jivaros who inhabit the valley of the Pastaza; the Zaparos who occupy the forest region between the Pastaza and Napo; the Piojes of the middle Napo, and eastward to the Putumayo; and the Iquitos and Mazanes of the lower Napo and Tigre, chiefly in territory occupied by Peru.