hy Alexander von Ilmiihuldt. xxxvii 



there flowed an extensive stream of lava in July 1844. It 

 would be most tempting; to pass by land from Mexico south- 

 wards to Oaxaca, and thence to the Isthmus of Guasacualco 

 or Tehuantepec, and Chiapas, so as to rejoin the frigate at 

 Realejo or Sonsonate. Facts might be obtained, in such a 

 journey, of great value in determining the dependence of 

 geological phenomena on each other ; but it is to be feared 

 it would be attended with too much fatigue and loss of 

 time. For similar reasons, it cannot be proposed that the 

 scientific gentlemen attached to the Expedition, should leave 

 the frigate for three or four months, when they reach Central 

 America, in order to cross by rail the Isthmus of Panama, 

 with the object of examining the Volcancitos of Turbaco 

 and Gabra Zamba, both active, and thence ascend the Rio 

 Magdalena from Carthagena de las Indias, as far as Honda, 

 whence they could proceed by Bogota and Popayan to Quito. 

 It will be also unavoidable to forego the examination of 

 the sedimentary rocks, rich in fossils, between Honda, 

 Bogota and Ibagues, the Mastodon fields (Campos del 

 Gigante), and the Salto de Tegumidama on the plateau of 

 Bogota, the wax palm (Ceroxylon Andicola), and the Azu- 

 frales of the Posto de Quindici, the volcanoes of Tolima, 

 measured by myself and ascended by Boussingault, and of 

 Paramo de Ruiz (4° 15' N.), as also the two volcanoes of 

 Popayan, the Purace and the much more interesting but 

 now extinct Sotara. As a middle course, I may suggest 

 a disembarkation, not exactly at Guayaquil, but on the gold 



