I have had much pleasure in finding that the travels of Sir Robert Schomburgk have fully corroborated these early views. The section of his map which gives the course of the Essequibo and of the Rupunuri is quite new, and of great importance in a geographical point of view. It places the Pacaraima chain between 3° 52′and 4° north lat., while I had given its mean direction from 4° to 4° 10′. The chain reaches the confluence of the Essequibo and Rupunuri in 3° 57′ north lat., and 58° 1′ west longitude; I had placed it half a degree too far to the north. Schomburgk calls the last-named river Rupununi, according to the pronunciation of the Macusis; and gives as the synonymes Rupunuri, Rupunuwini and Opununy, which have arisen from the difficulty the Carib tribes of these districts find in pronouncing the letter “r.” The position of the lake Amucu and its relations to the Mahu (Maou) and Tacutu (Tacoto) correspond perfectly with my map of Colombia drawn in 1825. We agree equally well regarding the latitude of the lake of Amucu, for while he places it in 3° 33′, I considered it to be in 3° 35′; the Caño Pirara (Pirarara) which connects the Amucu with the Rio Branco, flows from it towards the north, and not to the west as I had marked it. The Sibarana of my map, the sources of which Hortsmann placed to the north of the Cerro Ucucuamo near a fine mine of rock crystal, is the Siparuni of Schomburgk’s map. His Waa-Ekuru is the Tavaricaru of the Portuguese geographer Pontes Leme, and is the branch of the Rupunuri which lies the nearest to the lake of Amucu.