1917.] Chapman, Distribution of Bird-life in Colombia. 77 



to somewhere about Cabo de San Juan de Guia, where the forest of the 

 Sierra Nevada (as above quoted) . extends right down to the sea all along 

 the coast to a point known as Camarones, from which point to Rio Hacha 

 is a region of scrub and cactus, along the coast, but opening out into savanna 

 and scattered woodland toward the south, and continuing on around the 

 Sierra Nevada to the region of the Valle de Upar and Rio Cesar Valley. ... 

 The whole of the Goajira Peninsula, from Rio Hacha east, is an arid region 

 of cacti and thorny scrub." 



Hettner's reference to the savannas of the lower Magdalena, "some- 

 what north of 8 degrees or just north of the region of tropical rains'' has 

 been given in connection with his description of the Llanos quoted on a 

 preceding page. 



The two remaining unforested areas, the upper Magdalena and upper 

 Cauca Valleys, are described both in our itineraries and in connection with 

 the characterization of the Cauca-Magdalena fauna of which they form 

 arid sections. 



Hettner (Z. c, p. 79) referring to the upper Magdalena region writes: 



" Another interruption of the forest was probably formed by the strata 

 of sand and gravel, whose porous soil, destitute of nutriments, is not suffi- 

 cient for the forest; the mesa of Fusugasuga, for instance, probably always ' 

 consisted of thorny underbrush and grass. Similar, although still more 

 adapted to the drought, because it lies in a warmer climate, are the strata 

 of sand and gravel of Medina or the tuff plains on the Magdalena River 

 above Honda." 



The same author {I. c, p. 80) describes the vegetation of this and similar 

 semi-arid localities in this part of Colombia as follows : 



" In many places, the bushy vegetation shows plainly its adaptation to 

 drought, and this is generally the case in the vicinity of the lighter mimosa 

 forest, which probably took in the place of this brush originally. It is 

 small-leaved and thorny and generally shows the acacia form; the agaves 

 with their sword-shaped, sharp-edged, fleshy leaves, and the most varied 

 forms of cacti, whose juicy trunks give them the ability to overcome drought, 

 are numerous and often form impenetrable thickets, while at different spots, 

 they stand singly, and leave the bare earth between them. In such places 

 the land almost bears the appearance of a desert, and only the donkey finds 

 a meagre meal. This vegetation, adapted to the drought, occurs in almost 

 all the altitudes, on the banks of the Magdalena River above Honda, as 

 well as in the valley of the Rio Bogota between Tocaima and Jiradot, or 

 in the vicinity of Clicuta, and at Neiva, or at Soacha in the southern part 

 of the plateau of Bogota, but it is, however, more extensive and more devel- 

 oped in the lower, warmer parts than in the cooler altitudes." 



