HILL: GEOLOGY OF JAMAICA. 215 
relations of these beds in Jamaica indicate a later age. Deferring to 
Dall’s opinion, I have tentatively accepted his conclusions, however, 
i until more field work can be done. 
| This subsidence was the first of the group of oscillatory movements 
| which succeeded the great Mid-Tertiary Antillean orogenic displacement, 
and which in succeeding cycles apparently became gradually more epeiro- 
genic in character and successively of decreasing amplitude. While these 
movements in late Tertiary, Pleistocene, and recent time were far reach- | 
ing and apparently of uniform character over wide fields of extent, they 
were rather of the nature of great swells or wide gentle folds, with 
movements of opposite direction in their ultimate extension, and of a 
nature which cannot as yet be completely harmonized with those of 
our Atlantic Coastal Plain. Furthermore, while in some epochs the 
records of these movements are most clear and unmistakable, there 
are others which it is exceedingly difficult to interpret, and hence their | 
analysis as a whole is sometimes obscure. | 
Since the dismemberment of the Antillean lands through subsidence, | 
the aggregate of the upward movement has not been sufficient to restore 
the islands to the heights they occupied during the orogenic expansion. 
Wo have described with some care the various topographic levels which 
make great benches around the mountainous nucleus of Jamaica, and 
record phases in the physical history of the island. These levels prac- 
tically belong to three great groups, the oldest of which are from 1,500 
to 2,000 feet above the sea, and which may be called the Junki type; 
the next oldest, from 100 to 1,000, which may be called the Yumuri 
type; and the newest and most recent less than 100 feet. In a previous 
paper I have shown that these old levels are practically traceable around 
the island of Cuba, especially its eastern end. I can now add that they 
“are also similarly developed on the island of Haiti. There can be but 
little doubt that these three series of terraces are characteristic of the 
sreat Antilles adjacent to the Windward passage, while the two series 
are more widely identifiable. These stair-like terraces may record re- 
peated intermittent upward movements, or such movements alternating 
with epochs of subsidence. I was unable to find in the geologic forma- 
tions and structure any data to sustain the hypothesis of subsidence, 
It is difficult to establish the chronology of Post-Bowden events be- 
cause paleontology has given us no positive key by which we can dis- 
tinguish with exactness the formations of the Pliocene, Pleistocene, and 
recent epochs. The calcareous Post-Tertiary material composing these 
islands resolves into two distinct types: coral reef rock, and white lime- 
