622 T. W. VAUGHAX GEOLOGIC HISTORY OF CENTRAL AMERICA 



limestone containing Ortliophragmina on Haut Chagres and at David, 

 Panama, should be referred to the uppermost Eocene or to the basal Oli- 

 gocene. The Ocala limestone contains large stellate species of Ortho- 

 phragmina, and I collected a similar species in Saint Bartholomew. Of 

 the Eocene age of these deposits, of the typical Brito formation in Nica- 

 ragua, and of certain limestones containing Orthophragmina in Cuba 

 there seems to be no reasonable doubt; but, according to Douville, the 

 small stellate Ortliophragmina (subgenus Asterodiscus) ranges upward 

 into the lower Oligocene. The association of Asterodiscus and small, 

 even non-stellate, species of Ortliophragmina with species of Lepidocy- 

 clina that at some localities are found in association with a coral fauna 

 of middle Oligocene affinities has inclined me to the opinion that certain 

 peculiar species of Ortliophragmina occur in deposits of lower Oligocene 

 age. Doctor Cushman, however, is disposed to regard the beds in which 

 these species of Ortliophragmina were found as of Eocene age. At present 

 the evidence is not decisive and additional studies are needed. 



Paleogeographic Summary 



72v general 



As Doctor Stanton has summarized in the preceding paper of this 

 series the Mesozoic history of Central America, Mexico, and the West 

 Indies, and as his conclusions are incorporated in the tabular statement 

 on page — of this paper, I need not repeat anything he has said, but 

 regarding the Paleozoic history I will state a few of the important events. 



LATE PALEOZOIC 



The great Appalacliian revolution occurred in late Paleozoic, Permian 

 time, and resulted in the northern boundary of the Gulf of Mexico — the 

 southern Appalachian, the Ouachita, and Wichita Mountains. 



The east and west trend in southern Mexico and in southwestern 

 Chiapas already existed or was developed about this time, while farther 

 to the southeast, as Sapper has shown, Eio Motagua, in Guatemala, 

 divides two chains of this age — one to the north, the other to the south — 

 with spurs of a third chain farther toward the southeast. The nearly 

 north and south trend of the Coxcomb Mountains, in British Hon- 

 duras, which are composed of sediments apparently of pre-Paleozoic age, 

 indicates that the Yucatan protuberant had been outlined in Paleozoic, 

 perhaps early Paleozoic, time. Granitic debris in Costa Eica and Panama 

 suggests old deformation along east and west lines in those areas. The 

 east and west mountains of Venezuela have an old foundation and cer- 

 tainly date back to the Paleozoic in origin. There is evidence of old 



