1. Plan del curso de los Rios Huallaga y Ucayali y de la Pampa del Sacramento Maps University Of Minnesota Public content 1851. Sobreviela, Manuel, -1803. Relief shown by hachures.; "Senate Ex. Doc. No. 36, 2d Sess., 32d Cong." 40 x 27 centimeters Scale approximately 1:5,000,000 General Map Collection. Lith. by A. Hoen & Co (Baltimore, Md).