Mr. De la Beche on the Geology of Jamaica. 191 



it will be recollected^ I have noticed in two or three places in Jamaica. It is 

 stated, that in the red sandstone of Guanaxuato, the cement is so abundant 

 (road from Guanaxuato to Rayas and to Salgado) that the embedded fragments 

 can no longer be distinguished. Argillaceous beds_, from 3 to 4 toises thick, 

 are there seen to alternate with the coarse conglomerate : an alternation of 

 argillaceous beds also takes place with the red conglomerates of Jamaica 

 (Valley of the Hope River, &c). M. Humboldt mentions that he did not ob- 

 serve any traces of coal, or fossil wood, in the red sandstone of Guanaxuato, 

 but that these substances are frequently found in other parts of New Spain. 



Under the head of Venezuela, it is stated that the immense plains of Vene- 

 zuela (Llanos of the Low Oronoco) are in great part covered by red sandstone, 

 that the red sandstone is disposed in concave strata between the mountains of 

 the Caracas' coast and those of Upper Oronoco ; and that it rests on the north 

 on transition slate, and on the south on granite. This arenaceous formation is 

 covered (Tisnao) by a whitish gray compact limestone, resembling that of the 

 Jura. 



In New Grenada an extensive sandstone formation, which M. Humboldt 

 considers to be gres rouge, covers nearly without interruption, not only the 

 northern plains of New Grenada, between Mompox, the canal of Mahates, 

 and the mountains of Toiu and Maria, but also the basin of the Rio de la 

 Magdalena (between Teneriffe and Melgar), and that of the Rio Cauca 

 (between Carthago and Cali). Some scattered fragments of schistose coal 

 grit, which he found at the mouth of the Rio Sinu (to the E. of the Gulf of 

 Darien), lead him to think it probable that this formation extends even towards 

 the Rio Atrato and the Isthmus of Panama. It rises to considerable height 

 on the eastern branches of the Cordillera (Paramos de Chingasa and de Suma 

 Paz), and on the western in the mountains between the basin of the Rio 

 Cauca and the Platiniferous district of Choco. It is stated that this sandstone 

 of New Granada may be traced, without losing sight of it, from the Valley of 

 the Rio Magdalena (Honda, Melgar,) by Pandi to the platform of Santa-Fe 

 de Bogota. 



M. Humboldt informs us, that in the southern hemisphere, the Cordilleras 

 of Quito presented him with the most extensive formation of gres rouge that 

 he had yet observed. This rock covers, at the height of 1300 and 1500 

 toises above the sea, the whole plateau of Tarqui and Cuen9a ; it rises in the 

 Paramo de Sarar to the height of 1900 toises, and the thickness of its entire 

 mass exceeds 800 toises. 



The Cuen^a formation of grhs rouge is found in Peru, at the great plateau 

 of Caxamarca. 



VOL. II. SEC0>^D SERIES. 2c 



