818 REVIEWS 
underlie most of the island. The beds of the Blue Mountain series 
are much deformed. Since a continuous exposure of the total series 
is nowhere found, exact measures of thickness have not been 
obtained, but it is stated that the thickness probably exceeds 5000 
feet: 
The Blue Mountain series is made up of Upper Cretaceous and 
Lower Eocene beds. ‘There seems at this point to be a little confusion 
in the classification, since the Richmond formation, which appears to 
be the upper part of the Blue Mountain series, is classed as Eocene at 
some points (geological map), but as Upper Cretaceous at others (p. 
143). The Blue Mountain series is exposed in the central and western 
parts of the island at levels which are below the mountains of the east. 
In these localities, erosion has removed the overlying beds. 
The Blue Mountain series is overlaid by the Cambridge formation, 
a formation not extensively exposed. Where it appears, it skirts the 
older series. It is made up of clays, marls, and yellow limestones, 
and occupies a transitional position between the older series, the 
material of which was derived from land formations, and the next 
succeeding formation, the material of which is limestone, and therefore 
of oceanic origin. The Cambridge formation is classified as late 
Eocene. 
The Cambridge formation is followed in stratigraphic order by an 
extensive formation of White Limestone, the principal formation of the 
plateau. It has by far the widest surface development of any forma- 
tion on the island. It covers the whole of the island between the top 
of the plateau (3000 feet) and the coastal plain, and underlies some 
portions of the latter. In the western part of the island it completely 
covers (or once did) the Blue Mountain series. The beds of limestone 
are often considerably disturbed. The formation is assigned a deep 
water origin, since it contains neither reef corals nor littoral shells. 
Its fossils are mainly microscopic, and it is referred to the earlier part 
of the Oligocene period. 
The formations of the island younger than the White Limestone 
belong to the coastal series, and were made after great changes had 
affected the island. ‘These coastal formations are made up of four 
sorts of rock: (1) marine beds, (2) alluvium, (3) elevated coral reefs, 
and (4) littoral deposits. 
The oldest of these formations is known as the Bowden formation, 
the age of which seems to be in some doubt. It is regarded as either 
