752 WILLIAM F. JONES 
The peculiar depression between the south and central ranges 
is apparently a normally faulted block. The structure of this 
block is unknown. At only one point are the underlying rocks 
uncovered and here what are undoubtedly Oligocene-Miocene 
sediments are tilted at high angles. The indications are that this 
plain is a region similar to the central plain of Haiti, which was down- 
faulted to below sea level and has only been in part lifted above the 
sea in Pleistocene or Recent times. This is indicated by elevated 
coral reefs near Port-au-Prince. 
