630 



i 



stone covers the (jurassic) limestone of Cuma- 

 nacoa. Is it an arenacious rock, analogous to 

 green sandstone, or does it belong to the sand- 

 stone of Cocollar ? In the latter case, its pre- 

 sence seems to prove still more clearly, that 

 the limestones of Cumanaco and Caripe are 

 only two parts of the same system, alternating 

 with sandstone, sometimes quartzous, some- 

 times slaty. 



X. GYPSUM OF THE LLANOS OF VENEZUELA. 



Deposits of lamellar gypsum, containing nu- 

 merous layers of marl, are found by fragments 

 in the steppes of Caraccas and Barcelona ; for 

 instance, in the table-land of San Diego, be- 

 tween Ortiz and Mesa de Paja ; near the 

 mission of Cachipo. They appeared to me to 

 cover the (jurassic) limestone of Tisnao, which 

 is analagous to that of Caripe, where we find 

 it mixed with masses of fibrous gypsum (Vol. 

 iv, p. 386 ; Vol, vi, p. 49). I have not given 

 the name of formations, either to the sandstone 

 of the Oroonoko, or that of Cocollar, to the 

 sandstone of Bergantin, or the gypsum of the 

 LlanoSy because nothing hitherto proves the 

 independence of those arenacious and gypsous 

 soils. I presume it will one day be ascertained 

 that the gypsum of the Llanos covers not only 

 the (jurassic) limestone, of the Llanos, but is 



