Bulletin A. M. N. H 



Vol. XXXVI, Plate IV. 



Eastern side of Western Andes from San Antonio 



Note descent of forest down a drainage ravine and ascent of arid zone of the 



Cauca Valley up a treeless shoulder of the range. 



(Interdigitation of Tropical and Subtropical Zones and West Andean Fauna 



with arid portion of the Cauca-Magdalena Faima.) 



