816 REVIEWS 
is indicated by the title of the several parts of the volume. ‘These are 
as follows: Part I, Geography and Physiography; Part II, The 
Geologic Structure and Sequence; Part III, Paleontology of the 
Jamaican Sequence; Part IV, Relations of the Jamaican Formations 
to those of Adjacent Regions; Part VI, Changes of Physiography in 
Tropical America bearing upon the History of the West Indian Islands; 
Part VII, Appendices (1) Additional Note on the Geology of Porto Rico 
and Santiago de Cuba, and (2) Some Cretaceous and Eocene Corals 
of Jamaica (by T. Wayland Vaughan). 
Geography.— Geographically the island is described as follows: 
There is a central mountain axis in the eastern third of the island, the 
highest point of which is between 7000 and 8000 feet above sea level. 
About this mountain axis, with its chief extension to the west, is a 
plateau ranging from 1000 or 1200 feet, to 3000 feet. The plateau is 
really a gentle arch, and its greatest elevation is in the central part of 
the island. The plateau terminates abruptly by steep slopes known as 
the “‘back coast border.” The margins of the back coast border are 
irregular, the result of valley excavation. The plateau is chiefly of 
limestone, and its interior topography is largely the result of solution 
and interior drainage. The plateau contains many remarkable basins 
developed in this way. Some of them have no outlets, while others 
have recently been tapped by valleys working in from the margins of 
the plateau. The margins of the plateau are extensively terraced. On 
the east side of Montego Bay there are at least six terraces, and while 
the number elsewhere is fewer, some of them are at levels considerably 
above those shown at Montego Bay, so that the total number is more 
than six. ‘The terraces are much interrupted by erosion, the oldest being 
least distinct, and most discontinuous. The highest occurs at elevations 
of 1800 or 2000 feet, an altitude quite above the top of the back coast 
border in some parts of the island. The second highest terrace occurs 
at an elevation of about 1500 feet, the next at 1000 feet, and others at 
650, 300, and 200 feet respectively. The upper terraces appear to have 
been carved out of the limestone during the period of emergence which 
followed the deposition of the limestone. Those below 700 feet appear 
to have been carved in a later period of elevation, following a period 
of submergence, after the higher terraces were made. The terraces 
“have all been cut out of the land by gradational processes (base level- 
ing and marine erosion) and represent pausation stages in two long 
periods of elevation” (p. 33). 
