Huallaga River. Miles. Mouth of the Huallaga to Laguna 17 Laguna to Santa Lucia 26 Santa Lucia to Santa Maria 55 Santa Maria to Yurimaguas 26 Yurimaguas to Cainarachi 38 Cainarachi to Rumicallarina 8 Rumicallarina to Chasuta 50 Chasuta to Lake Chiquicoba 300 --- Length of the Huallaga river 520 Distance from the source of the Huallaga to the mouth of the Amazon 2950 UCAYALI RIVER. The Ucayali river has its origin in the Andean region, about Lake Titicaca, and flows, under various names, in a direction nearly north until it mingles its waters with those of the Amazon, to which river it bears the same relation that the Missouri does to the Mississippi; that is to say, like the Missouri, its length and volume of water entitles it to be considered a continuation and not a tributary of the main river. During the season of low water 24 feet can be carried from Nauta, at the mouth of the river, to Sarayacu; 18 feet from Sarayacu to the mouth of the Pachitea river; and 12 feet from the mouth of the Pachitea to the confluence of the Tambo and Urubamba. The average current from the mouth of the river to Pucacura is 2 miles per hour, and from Pucacura to the confluence of the Tambo and Urubamba 3 miles per hour. The Tambo is probably navigable for steamers drawing eight or ten feet of water to the confluence of the Ene and Perene, and thence the Perene would afford communication, at least by canoes, to San Ramon, a Peruvian military post; from San Ramon to Tarma, and from Tarma to Lima, would, of course, be the continuation of the route to the Pacific slope. The first step towards the opening of this most desirable of all the routes between the Pacific coast and the Amazon would be the establishment of a battalion post at the confluence of the Ene and Perene, communicating at regular and stated intervals with San Ramon. The distance between the two posts would be about 60 miles of canoe navigation, and would soon become a traveled route forming the connecting link between eastern and western Peru. MOUTH OF THE UCAYALI. Latitude, 4 deg. 28' 30" south; longitude, 73 deg. 21' 30" west of Greenwich; magnetic variation, 7 deg. 2' east; thermometer, 80 deg.; elevation above sea-level, 318 feet; distance from the Atlantic, 2180 miles; current, 2 miles per hour; the width of the Ucayali at its mouth is half a mile. PUCACURA.