90 BULLETIN: MUSEUM OF COMPARATIVE ZOÖLOGY. 
Fossils! are generally missing from the Kingston formation; specu- 
lation concerning its age must be founded entirely upon stratigraphical 
relations. In our opinion it is clearly older than the elevated reefs of 
the Barbican and Hopewell formations of presumable Pleistocene age, 
and younger than the Bowden formation, being nearly allied by position 
to the age of the Manchioneal which we consider Pliocene. 
The present beds of both the Hope and the Cobre Rivers deeply 
indent the Kingston formation, eutting far below the surface of the 
plain. The alluvium of these stream valleys and their general level 
constitute distinct deposits which are later described under the head of 
the Montego formation. 
The Elevated Reefs. — The coast of Jamaica, like many of the other 
West Indian Islands, is in places bordered by a peculiar formation 
composed of rocks which were once growing coral reefs similar to those 
now bordering the island, and which have been raised above sea level 
by general regional elevation in late geologic time. These formar 
tions are found in small, limited, interrupted areas in Jamaica immedi- 
ately adjacent to the coasts, and at altitudes of less than seventy-five 
fect. They do not have the wide areal development which is seen on 
the north coast of Cuba, nor do they veneer the higher summits as in 
Barbados. 
The elevated reef rocks usually constitute horizontal beds of strata 
from ten to forty fect in thickness. These have a more or less massive 
exterior, due to surface induration, but when cut into, as they frequently 
are by the undermining of the sea or in the construction of highways, 
their interior structure is seen to consist of porous limestone material 
of varying texture, always more or less minutely honeycombed, and of 
irregular hardness, with red oxidized spots or yellow patches here and 
there. They show all degrees of induration, from that of the p ractically 
unchanged reef material to firm semi-crystalline white limestones. 
These rocks are composed of coral heads of various sizes embedded in 
a matrix of marl, — the latter being sometimes indurated into limestone: 
The heads usually have the erect position which they maintained when 
they were growing organisms. Some of these are of great size, one 
specimen, which can be distinguished in the illustration on Plate XXIX» 
was six feet in height. The marl represents the reef débris which 19 
found between the growing or dead coral heads of living reefs, and 1s 
1 Brown, in the Jamaican Reports, page 166, describes a formation similar to 
that of the Kingston in the parish of St. Elizabeth along the coast from Alligator 
Pond Bay to Green Day, in which remains of land shells are found. 
