In 1840 Mr. Wheelwright was commissioned by the directors of the Pacific Steam Navigation Company to examine the capabilities of the river Chagres, and the best means of communication with the South Sea. He made a lengthy report on the subject, in the course of which he confirmed many of Captain Lloyd’s observations, giving the depth of high water on the bar of the Chagres at 15 feet. In 1843, again, M. Napoleon Garella received from M. Guizot, as Minister of Foreign Affairs, an order to make a survey of the isthmus, and he proposed a summit-canal of more than three miles long, the level being reached by thirty-six locks and three large aqueducts.[173] In 1853, Mr. Squier explored that section of the mountain chain which crosses the American isthmus to which Berghaus has given the name of the Honduras-Nicaraguan group. This range commences at the Col de Guajoca and extends to the valley of the Rio San Juan. Running at first close to the shore of the Pacific, it gradually approaches the centre of the isthmus. The eastern slope, broken by mountain offshoots and watered by rivers of the first order, terminates on the north-east in the point Gracias a Dios. The western slope forms a long, low, and, comparatively speaking, level valley, crossed by an irregular and independent series of volcanic peaks. This accessory line of volcanoes, which presents the most distinctive feature of the physical geography of Central America, is nowhere so distinct from the main line of rocky axis as in the Honduras-Nicaraguan district. Mr. Squier proposed to commence a railway at Puerto Caballos, in the Bay of Honduras, and proceed due south to Fonseca Bay, on the Pacific, a distance of some 160 miles. The harbours on this route are said to be very superior to those on the Tehuantepec route. The summit-level, however, is 2308 feet above the level of the sea. At such a height a canal would be practically impossible, and the project was never carried any further than a survey.