820 REVIEWS 
The topography and stratigraphy of the island suggest the follow- 
ing sequence of events : 
1. The first event in the history of the island so far as now known 
is the igneous activity which furnished the material for the Blue 
Mountain series. This was probably in Cretaceous time. The oldest 
formation of the island is composed of the débris of this activity. The 
amount of the débris was great, indicating that the volcanic activity 
was extensive. 
2. The degradation of the volcanic débris and the re-deposition of 
the material in the form of sedimentary formations (the Blue Mountain 
series) was the second great event in the history of the island. The 
formation is such as to show (a) that there was rapid erosion and 
deposition ; (4) that the land from which the sediments came was 
high ; and (c) that the deposition was accomplished in shallow water. 
3. The next event was the elevation, and, perhaps, the folding, of 
the beds of the Blue Mountain series. The folding probably followed 
the deposition of the Richmond (Eocene) formation; that is, was mid- 
Eocene. On this point, however, the author is not altogether satisfied, 
and indicates that the folding may possibly have occurred later. 
4. The next event was the sinking of the island, probably late in 
the Eocene period, followed by the deposition on the submerged surface 
of the great White Limestone formation. The subsidence is estimated 
to have been at least 1200 fathoms. This great subsidence submerged 
all but the higher parts of the Blue Mountain series, leaving at most 
only the parts which are now more than 3000 feet high out of water. 
The subsidence may have been even greater, submerging the whole 
island. The evidence of this great subsidence is found in the Mont- 
pelier chalk (the lower part of the White Limestone), the composition 
of which indicates, according to Mr. Hill, a depth of 1200 to 2300 
fathoms. Further evidence of the great subsidence is found in the 
stratigraphically equivalent radiolarian earths in eastern Cuba—earths 
which call for depths of 3000 to 4ooo fathoms. Mr. Hill thinks it 
would not be unfair to assume 10,000 feet as the mean subsidence of 
Jamaica (p. 165). The argument of Mr. Hill for so great a sinking 
does not seem altogether conclusive. If the whole of the island were 
submerged, and this would not seem to call for so great a subsidence 
(though still a great one) there is no apparent reason why formations 
due to pelagic life should not be made in shallow water, even though 
too deep for corals and other shore-life. A few hundred feet of water 
