639 



destitute of spangles of mica, but inclosing sele- 

 nite and lamellar gypsum. These shelves of 

 clay appeared to me to form constantly the 

 lower layers. There also belongs to this ter- 

 tiary soil, the limestone tuf (fresh water forma- 

 tion) of the vallies of Aragua (Vol. iv, p. 109, 

 186)^ near Victoria, and the fragmentary rock 

 of Cabo Blanco, at the west of the port of la 

 Guayra. I dare not designate the latter by the 

 name of nagelfluhe, because that word indi- 

 cates rounded fragments, while the fragments 

 of Cabo Blanco are generally angular, and 

 composed of gneiss, hyalin quartz, and chlorit- 

 ous slate, joined by a limestone cement. This 

 cement contains magnetic sand *, madreporites, 

 and vestiges of bivalve pelagic shells. The 

 different fragments of tertiary soil which I 

 found in the Cordillera of the shore of Vene- 

 zuela, on the two slopes of the northern chain, 

 seem to be superposed near Cumana (be- 

 tween Bordones and Punta Delgada), in the 

 Cerro of Meapire, on the (alpine) limestone of 

 Cumanacoa ; between Porto Cabello and the 

 Rio Guayguaza, as well as in the vallies of 

 Aragua, on granite ; on the western declivity 

 of the hill formed by the Cabo Blanco, on 



* The magnetic sand is no doubt owing to chloritous 

 slate, which, in these latitudes, forms the bottom of the sea. 

 Vol. iii, p. 404; Vol. vi, p. 610, 



