Pre-Colombian Jamaica: Caribbean Archeology and Ethnohistory

Environment, Fauna, and Flora / 51
spectively, each constituting riftlike features or grabens. They are delineated by
NW- SE trending fault lines, which are matched by another set of lesser W- E
fault lines on the north and south coasts. The Wagwater belt in particular was
filled with a complex succession of deposits: (1) coarse grained terrestrial breccias
and conglomerates, known as the Wagwater Formation; (2) extrusive volcanic
flows from three dacite centers, known as the Newcastle Volcanics; and
(3) marine sandstones and shales, known as the Richmond Formation. This
heralded an island- wide marine transgression that was characteristic of the
middle Tertiary, from the middle Eocene to the middle Miocene about 12 million
years ago. The traces of this marine transgression are found all over Jamaica
today. As Robinson states, “probably no part of the island region was more than
a few metres above sea level at any time” during this period. Two phases are represented,
first the Yellow Limestone and then the White Limestone. The Yellow
Limestone consists of a mixture of limestone and clastic sedimentary rocks
deposited in fluvial to offshore marine environments. The White Limestone
“super group” (with 11 Formations) consists of more or less pure carbonates, deposited
in deep water, high energy open shelf, and low energy lagoonal settings.
White Limestone presently forms more than half of the island’s surface, and
if all limestone outcrops of whatever type are included the total rises to twothirds.
Hence it is not surprising that Anthony Porter refers to calcium carbonate
(calcite) as “the foundation mineral of Jamaica, just as limestone is the foundation
rock.” Chemical erosion has transformed many of the limestones into
karst landscapes of which the Cockpit country is the most spectacular.
The late Tertiary saw Jamaica once again emerge from the sea, and there
was renewed tectonic activity, as well as extensive erosion (which revealed the
inliers) and corresponding sedimentary deposition, which continued into the
Quaternary from about 2 million years ago. In the first place, the erosional
process created what is referred to as the Coastal Group, a discontinuous series
of deposits formed by fl uvial transport of material from the interior, particularly
well shown at Bowden, Manchioneal, and Buff Bay, along the north
coast between Port Maria and Ocho Rios, and south of Negril. Finally, in the
Quaternary, the alluvial flat lands of southern Jamaica were formed, including
the Liguanea, St. Jago, and Vere Plains, as well as the St. Georges Plain around
Frome.
Unfortunately, not a great deal has so far been done to study the fluctuations
of Quaternary climate and environment in Jamaica. What has been done is
concentrated in the southwest of the island, in the Negril and lower Black River
morasses (Digerfeldt and Hendry 1987; Hendry 1981; Hendry and Diger feldt