Immediately south of Chinaja is a range of hills, the Serrania de
Chinaja, having an almost due east-west axis and a crest of about 600
meters above sea level. South of the Serrania de Chinaja are
succeedingly higher ridges building up to the Meseta de Coban and Sierra
de Pocolha and eventually to the main Guatemalan highlands. The northern
face of the Serrania de Chinaja is a fault scarp dropping abruptly from
about 650 meters at the crest to about 140 meters at the base. From the
base of the Serrania de Chinaja northward to the Rio de la Pasion at
Sayaxche the terrain is gently rolling and has a total relief of about
50 meters. North of the Rio de la Pasion is a low dome reaching an
elevation of 170 meters at La Libertad; see Stuart (1935:12) for further
discussion of the physiography of central El Peten. The rocks in
southern El Peten are predominately Miocene marine limestones; there are
occasional pockets of Pliocene deposits. There is little evidence of
subterranean solution at Chinaja, but northward in central El Peten
karsting is common. The upper few inches of soil is humus rich in
organic matter; below this is clay.