394 ANNUAL REPORT SMITHSONIAN rNSTITUTlON, 1956 



The rainfall at Villavicencio, 500 meters above sea level, is high, 

 with an average for the 6-year period (1941 through 1946) of 4,670 

 millimeters (184 inches). It is fairly well distributed throughout 

 the year, with more than 400 millimeters a month from April through 

 November. The evaporation rate is high and the runoff rapid, and 

 one does not feel any marked oppressive humidity. Temperatures 

 at night are about 70° F. and the maximum day temperatures fluctu- 

 ate between 86° and 93° F. 5 Thus cool evenings and nights follow 

 hot days in pleasant succession, and the annoyances that are thought 

 of by so many people as being synonymous with a tropical climate 

 are minimal. 



Precipitation at Buena Vista, 1,200 meters above sea level but only 

 6 kilometers from Villavicencio, is 6,400 millimeters, or just twice 

 that received at Puerto Lopez, 75 kilometers east of Villavicencio, 

 which is the head of navigation on the Meta River. 



From the Venezuelan frontier southward and westward to the 

 Macarena Massif (some 50 miles southwest of Villavicencio), stretches 

 of savanna alternate with densely forested areas. From the Macarena 

 mountains to the border with Ecuador, the entire area is forested. 

 This steep-sided block-fault mountain seems to lie in a zone with a 

 climate transitional between that of the Orinoco area, where the wet 

 and dry seasons are marked, and the Amazon region in which abun- 

 dant precipitation falls throughout the year ; 6 further, although itself 

 uninhabited and located in a sector where there are at present no 

 permanent settlements, impressive petroglyphs are to be seen that 

 have been carved in hard quartzite. 7 



SOILS 



The extremely sandy, permeable soils of many of the foothills and 

 of the alluvial fans laid down by intermittent streams have been used 

 largely as open range for what too often is rangy scrub cattle. Pros- 

 pects for crop production on such soils are poor. However, low 

 yields of dry rice could probably be obtained. In general it would 

 probably be best left as rangeland on which improved pasture could 

 be introduced. It might be mentioned, however, that many of our 

 concepts of geography, acquired in middle latitudes, may be subject 

 to revision. Marked and rewarding changes might perhaps be inau- 

 gurated in the cropping practices of these soils if the annual savanna 

 fires are prevented, if the hard crust is broken up by deep plowing, 



B Bates, Marston, Climate and vegetation in the Villavicencio region of eastern 

 Colombia, Geogr. Rev., October 1948, p. 570. 



6 Philipson, W. R. ; Doncaster, C. C. ; and Idrobo, J. J., An expedition to the 

 Sierra de la Macarena, Colombia, Geogr. Journ., vol 117, pt. 2, p. 191, June 1951. 



7 Gansser, August, Altindianische Felszeichnungen aus den kolumbianischen 

 Llanos, pp. 85-98. 



