MARINE ŠEDIMENTATION. 
VULCANISM, 
CENOZOIC. 
Pleiostocene and Recent. 
Recent or late 
Pleistocene. 
( 
Pleistocene. | 
( 
Marginal reefs of Caribbean Coast. 
Playas deposits at Panama. 
Swamp levels deposits of Caribbean 
Coast. 
Islands of Boco del Torro (Gabb). 
Panama Section. 
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|Otigocene| Miocene. | Pliocene. 
Limon (Moen) beds of Costa Rican 
Coast. 
Costa Rica Section. 
Quartz trachyte; vol- 
canie ash; porphy 
rite basalts of crater 
flows. 
Fringing Coral Reefs of Limon, Colon, 
etc. May have commenced in Pleis- 
tocene or even Pliocene epoch. 
Slight epeirogenic uplift of Isthmian 
region ; restoring drowned lands in 
part; but not in entirety. 
Deposition of fringe of Marine Pleis- 
tocene sediments. 
Subsidence, resulting in drowning of 
mouths of oid river valleys and of 
Panama Bay. 
No evidence of Post-Miocene 
Vulcanism. 
Miocene (Upper 
Miocene of older 
usage). 
Missing in Isthmian Section. 
Probable time of ** Sye- 
nitic”’ intrusions of 
San Blas and Tala- 
manca. 
Theralite, Trachyte An- 
desite, Hornblende and 
Pyroxene Andesites. 
Pyroclastic Trachytic 
lavas. 
Epoch of active and extensive erosion, 
accompanied by base levelling of the 
newly elevated land, and the cutting 
out of the swamp level bights of an- 
cestral valleys of present drainage. 
| Granitoid and Syenitic 
porphyrites probably 
intruded here. 
Tremendous  orogenic 
whereby theland was greatly ele- 
vated, and configuration of the 
Caribbean region rearranged. 
movements 
Chipola. 
Vicksburg. 
Monkey Hill Beds of Colon; Bo- 
nilla Beds of Costa Rica. 
Guallava Beds of Costa Rica. 
Apparent termination 
of period of basic 
eruptives in Isthmian 
ection. 
Littoral of the Caribbean Sea extended 
inland of its present margin, against | 
the older continental land, then cov- | 
ered as now by dense vegetation. 
Claiborne-Tejon. 
Older Eocene. 
Mindi Hill Beds. 
Gatun (Vamos á Vamos) and prob- 
ably Chipoango localities of 
Maack. 
1 Foraminiferal Beds of Bujio. 
1 Empire Limestone. 
Culebra clays, and probably much 
of the lower portion of the Ter- 
tiary sediments of Costa Rica. 
BI. 
PRE 
TERTIARY. 
| Cretaceous and 
Un 
Panama Formation (including 
stratified rhyolitic tuffs of 
anama, Miraflores, Barbacoas, 
and San Pablo). 
Cretaceous limestones of Costa 
Rica (San Miguel Formation). 
Active vulcanism. 
Augite andesites and 
porphyrites, inter- 
stratified with other 
sediments; also horn- 
blendic andesites and 
porphyrites. 
Formation. 
? Unlocated ` granites 
brought down by 
floods of Chagres. 
| Rhyolites of Panama 
Vulcanism more or less continuous to present epoch, 
Augite  andesites of 
Aguacate region. 
A shallow passage or passages be- 
tween the two oceans existed some- 
where in Tropical America during 
this epoch. 
Granites of Siquieres 
and unknown locali- 
ties, the débris of 
which is found in the 
Tertiary sediments 
of Costa Rica. 
An extensive land area probably 
existed towards the present Pacific 
side of the continents during these 
epochs. 
1 These beds may be identical, and possibly later than the Mindi Hill Beds. 
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“72901002 TAILVUVAWOO AO WARSAW :NILHTTNAA 
