220 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY, 
In the region of the Bahamas, according to A. Agassiz, subsidence has 
been "progressing during epochs which correspond with these regional, 
uplifts in the Antilles. 
The uniformity of this epeirogenic movement is also broken at two 
places by synchronous orogenic deformation: on the Leeward sido of the 
Windward Islands, where the modern reof rock is found 300 feet above 
the sea in disturbed patches, and at Port Limon, Costa Rica, where the 
Pleistocene beds are deformed. Furthermore, at the eastern extremity 
of the region, the island of Barbados, the Post-Pleistocene uplift is en- 
tirely discordant with that of all the rest of the region, the coral reefs of 
Barbados having risen to an altitude of 1,100 feet, 
Synchronously with the rising of tho reef, volcanic piling has continued 
on the mainland and in the Windward Islands, although the mass of 
ejecta during these later days is Lilliputian in comparison with the great 
heaps of débris piled up in preceding epochs. The present craters and 
vents of the Mexican, Costa Rican, and Windward summits are mero ant- 
hills capping the older mountains of ejecta. The last volcanic fires of the 
Cordilleran region of northern Mexico and the United States expired in 
Pleistocene time, 
The differing altitudes of the synchronous elevated reefs teach some 
important lessons. On close analysis they show that the apparent uni- 
formity of uplift does not persist, and resolves itself into a wide, swell- 
like movement, with different intensities in various parts of the field, 
gradually decreasing towards the United States, where hitherto Post- 
Pleistocene movements of the West Indies and the continent had been 
considered so uniformly continuous. These inequalities in the Post- 
Pleistocene uplifts of the West Indies also controvert the position main- 
tained that the elevated terraces might be due to shrinkage.of the sea 
rather than elevation of its bottom. 
The data presented are insufficient to show enough expansion of tho 
West Indian lands in Post-Oligocene times to have connected tho islands 
with the mainland or with one another, or to have created a continuous 
Windward bridge, as has been alleged. 
RÉSUMÉ. 
With the data presented, we can now briefly review the major pro- 
cesses of diastrophism which have produced these great changes of level 
in the Tropical region in later Mesozoic and Cenozoic times, and their 
effects upon the configuration of the lands. 
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