599 



on any particular formation of America, are 

 founded only on the supposed analogies be- 

 tween the formations of America and those of 

 Europe. Now, those names cannot remain the 

 same, if, after further examination, the objects 

 of comparison have not retained the same place 

 in the geognostic series ; if the most able geo- 

 logists now take for transition limestone, and 

 green sandstone, what they took formerly for 

 zechstein, and variegated sandstone. I believe 

 the surest means by which geognostic descrip- 

 tions may be made to survive the change which 

 the science undergoes in proportion to its pro- 

 gress, will be to substitute provisionally, in the 

 description of formations, for the systematic 

 names of red sandstone, variegated sandstone, 

 zechstein, and jura-limestone, names drawn 

 from American localities (sandstone of Llanos, 

 limestone of Cumanacoa and Caripe), and to 

 separate the enumeration of facts which are re- 

 lative to the superposition of soils, from the 

 discussion on the analogy of those soils * with 

 those of the antient continent. 



* The whole of positive geography being nothing but a 

 problem of the series or succession (either simple or periodi- 

 cal) of certain terms which represent the formations, it will 

 be necessary, in order to understand the discussions con- 

 tained in the third section of this memoir, to recapitulate 

 succinctly the table of formations considered in the most ge- 

 neral point of view. This sketch will rectify what was pub- 



