GEOLOGY OF GUATEMALA AND SPANISH HONDURAS 523 
Pacific Ocean at no great distance from shore and the parallelism 
to the coast line of the submarine contours are not unfavorable to 
the theory of subsidence. 
Diastrophic movements of considerable magnitude have taken 
place in Central America at three different periods: at or before the 
close of the pre-Cambrian, at the close of the Paleozoic, and during 
the late Miocene. A later movement may be dated as late Pliocene ~ 
or Pleistocene. The Cordilleran axes were developed during the 
folding at the close of the Paleozoic, the folding being most intense 
toward the south. Miocene movements, though less intense, 
developed parallel Cordilleran trends of the Caribbean system and 
initiated the cycle of erosion in which the greater part of the 
dissection of the present mountains was accomplished. Vulcanism 
undoubtedly began in the present central portion of the Isthmus 
before the Miocene deformation, as the earlier volcanics are steeply 
folded. Pliocene and Pleistocene (?) sediments from Yucatan 
southward through Honduras show evidence of both vertical and 
tangential movements, tangential movements being especially 
notable in the youngest sediments of the Atlantic Coast region 
near Puerto Cortez and Omoa, Honduras, and Lake Izabal, 
Guatemala. ; 
