Biology Reference
In-Depth Information
Figure 2.27
Physiography of the Antilles. Map created by Trisha Distler, Missouri Botanical
Garden, St. Louis, based on the U.S. Geological Survey's Shuttle Radiography Topography
Mission (SRTM) 90m DEM digital elevation database.
recently has its history been reconstructed to give a clearer picture of the
origin and development of the Antilles.
In the Middle Jurassic through the Early Cretaceous (200-165 Ma) the
continents were arranged as shown in fi gure 2.19 with proto-Venezuela sit-
uated in the developing Gulf of Mexico. North America and South America
(with Africa attached) began to separate, resulting in a shallow sea with
widespread evaporites and salt domes. These domes are the site of extensive
salt and oil deposits in the Gulf of Mexico region, and their collapse or ac-
cidental penetration can cause dramatic happenings on the surface.
In the southeastern United States, the arched surface over these domes
creates “islands,” circular stands of oak surrounded by more moist vegeta-
tion, lakes, or swamps. One of these is Jefferson Island, site of the Live Oak
Botanic Gardens in Lake Peigneur near New Iberia, Louisiana. New Iberia
is home to an extraordinary concentration of Cajun relatives named Via-
tor, and to the McIlhenny Tabasco Company on Avery Island. The region's
botanical claim to fame is the Evangeline oak immortalized in Longfellow's
