82 GEOLOGICAL RECONNAISSANCE OF THE DOMINICAN REPUBLIC. 



40 meters. Along the Barahona coast shells of species that are still extant 

 were found on a terrace at an altitude of 20 meters. 



The course of events along the Dominican coast subsequent to the 

 deposition of the "coast limestone" may have been as follows: 



1. Elevation of at least 100 meters, with intermittent pauses during 

 which wave-cut terraces were formed. 



2. Active erosion during which deep valley notches were cut across the 

 "coast limestone." 



3. Depression that produced drowned valleys, which indent the coast 

 and furnish the harbors, such as Puerto Plata and Samana Bay. The 

 depression occupied by Lake Enriquillo probably dates from this time. 

 It may have been cut off from Neiba Bay by delta deposits of Rio Yaque. 



4. Elevation as the latest event. The elevation appears to have been 

 about 35 meters in Barahona Province but was very different in other parts 

 of the island. The chief evidence of elevation in Barahona Province is the 

 well-defined coquina and coral reef terrace around Enriquillo Basin, which 

 is very conspicuous at Barbacoa, Neiba, and Duverge. To the traveller 

 passing over this forest of corals, some still bearing their original colors, 

 its resemblance to a modern coral reef as seen at low tide is striking. 

 There is also evidence that a slight elevation was the latest event in other 

 parts of the Republic, especially in the vicinity of Monte Cristi and Samana 

 Bay. 



The course of events has probably been much more complex than that 

 outlined above. There may have been in addition minor oscillations. 

 The "coast limestone" itself is made up of strata of ages ranging from 

 Miocene to Recent, and it may have been elevated above the sea in late 

 Pleistocene or Recent time, for the corals and other fossils found in it along 

 the sea front are identical with forms now found in the adjacent sea. 



Volcanism probably recurred in early Pleistocene time and has been 

 practically continuous almost to the present. There is no historic record 

 of late volcanic activity, but it is denoted by the recent aspect of some of 

 the volcanic vents and lava fields in the province of Azua. Hot springs that 

 may be regarded as phenomena associated with final stages of volcanism 

 are reported to occur at a few localities in the Cordillera Central. 



