Manual de Plantas de Costa Rica | The physical environment | 57 
volcanic in origin (although geologically allied with the Cordillera de Guanacaste), and 
Cerro San Miguel (414 m), near Miramar, is a volcanic dome (Tournon & Alvarado, 
1997). See Clark et al. (2000: 22) for other possible volcanic foci in the Cordillera de 
Tilaran. 
Offset slightly eastward from the axis of the Cordillera de Tilaran (and thus aligned 
with the axis of the Cordillera de Guanacaste) is the actively volcanic Cordillera Cen- 
tral, backdrop to the Central Valley. The Cordillera Central is home to the most impos- 
ing and familiar Costa Rican volcanoes (northwest to southeast): Volcan Pods (2708 
m); Volcan Barva (2900 m); and (off the Continental Divide on the Caribbean side) Vol- 
can Irazi (3432 m) and Volcan Turrialba (3329 m). Of these, only Pods and Irazti are 
presently regarded as active, although Volcan Turrialba is in the fumarole stage and was 
active as recently as 1866 (Tournon & Alvarado, 1997). These main peaks are flanked 
by subsidiary volcanoes, all extinct, including: Cerro Congo (2014 m), on the Carib- 
bean slope of Volcan Pods; Cerro Cacho Negro (2150 m), on the Caribbean slope of 
Volcan Barva; Cerro Zurqui (2010 m), between Volcan Barva and Volcan Irazu; and 
Cerro Pasqui (2554 m), on the southern slope of Volcan Irazu. 
The westernmost portion of the Cordillera Central, situated to the Caribbean side of 
the Continental Divide, is lower and less well known. The highest promontories in this 
region are: Cerro Pelén (ca. 2322 m); Cerro Palmira (2184 m); Cerro Porvenir (2267 m); 
Cerro (or Volcan) Platanar (2183 m); and Cerro Volcan Viejo (ca. 2183 m). At least the 
last four of these represent volcanoes that are presumably extinct, although Cerro Vol- 
can Viejo was still in the fumarole stage until 1960 (Tournon & Alvarado, 1997). 
The northern slope of the Cordillera Central is dissected by deep gorges, with rivers 
discharging large volumes of water toward the sea. Various small lakes of volcanic ori- 
gin (Laguna Hule, 730 m; Laguna Maria Aguilar, 775 m; Laguna Rio Cuarto, 390 m; 
etc.) dot the region. 
The Cordillera de Talamanca, extending from near Cartago southeastward into 
Panama, is the most extensive upland region in Costa Rica, with the highest summits. 
Slightly offset toward the west from the line of the Cordillera Central, it is thus aligned 
with the Cordillera de Tilaran and, like that range, is not actively volcanic. The Pacific 
slope of the Cordillera de Talamanca is, in general, much steeper than the Caribbean 
slope. The highest Talamancan peaks are Cerro Chirrip6 (3819 m), the highest in the 
country, and Cerro Kamuk (3549 m), lying off the Continental Divide to the Caribbean 
side. Both of these, as well as Cerro Cuerici (3345 m), show evidence of Quaternary 
glaciation about their summits, including moraines, cirques, small lakes, striated rock 
surfaces, etc. (Weyl, 1980; Gomez P., 1986; Tournon & Alvarado, 1997). Other impor- 
tant Talamancan peaks are Cerro Buena Vista (3491 m), known popularly as Cerro de La 
Muerte, located just off the Continental Divide to the Pacific side; Cerro Asuncié6n 
(3396 m), the highest point along the Pan-American Highway; and Cerro Vueltas (3156 
m), also on the Pacific side. 
