Ucayali
a river of eastern Peru; one of the main affluents of the Amazon, of which it was formerly regarded as the head stream. This honor is now accorded, however, to the Marañon, which, though shorter than the Ucayali, UDALL is twice as broad as the latter at their confluence . The Ucayali rises in the mountains of southern Peru, some of its feeders having their sources only 150 miles from the Pacific on the one hand, and 100 miles from Lake Titicaca on the other. In its upper course it is known as the Apurimac, and below the junction of the Mantara, in lat. 12° S., it is called the Tambo. After receiving the united waters of the Urubamba and Camisea in lat. 9° S., it becomes known as the Ucayali. Its entire course is about 1,500 miles. The Ucayali has been navigated by steamers for a great part of its course, and a steamer has penetrated by the Pachitea, a tributary on its left bank, to within 220 miles of Callao. The exception, and that of a fall on Apurimac is not navigable; but with this Lower Urubamba, the Ucayali and its principal tributaries are most valuable highways to the heart of a region abounding in vegetable and mineral wealth. the