MP' 



166 The Geological Age of the Mountains of Sta. Marta. 



whole Cretaceous period, 

 a folding of them took 

 place in Tertiary times, 

 by which the Sierra de 

 Perija was produced, 

 &c." 



The accompanying 

 profile surveyed by me 

 in the district of Papaijal 

 on the river Rancheria (5) 

 (Bio Hacha) and com- 

 pleted near Tomarazon 

 in the west, and passing 

 through the mountains 

 Cerrejon (2) and Potrero 

 de Venancio (3), gives 

 an indication of the stra- 

 tification of the rocks be- 

 tween the Sierra Nevada 

 (4), and the Cordillera 

 of Ocana (Perija) which 

 terminates here (1). — 

 a, a, a, Red marly sand- 

 stone and laminated marl, 

 alternating above with 

 calcareous Cretaceous 

 beds*; b. Tertiary strata; 

 c. Porphyry with copper 

 ores ; d. Red quartz- 

 porphyry ; e. Plutonic 

 rocks, such as also form 

 the nucleus of the Sierra 

 Nevada. 



* In the uppermost, pale- 

 blue limestone beds of the 

 younger Cretaceous there are, 

 in this district, near Chorrera, 

 towards the summit of the 

 hill, the so-called " Geologi- 

 cal organs," — perpendicular, 

 cylindrical shafts, in parts 

 10-12 m. high and 4-5 m. in 

 diameter, which I have fully 

 described in the Zeitschr. d. 

 Geol. Gesellsch. 1862, and in 

 Westermann's Monatsheften, 

 1863. 



