42 Bulletin 30 458 



sands. The latter are followed by the comparatively recent flood 

 plain deposits. The fossils have not yet been identified so exact 

 comparisons are not possible yet certain analogies are suggested. 

 Thus near Bucaro, 27 miles west of Santo Domingo City at the 

 copper mines, beds of tuffs occur capped by limestone. These 

 seemingly correspond to certain of the Porto Rican tuffs. The 

 Lares shales may go with the Orthaulax zone of the Yaqui Valley 

 or perhaps with the probably older Monte Cristi range. The lime- 

 stones and marls above the Lares shales perhaps correspond to 

 our Aphera and Sconsia formations. The terraces recall the Do- 

 minican terraces seen from Hato Viejo, while the flood plain de- 

 posits are probably synchronous with t he flood plain of the Rio 

 Yaqui. 



Correlation of the Yaqui Valley Horizons with those of 

 France and Florida.- — The resemblance of the fossil shells from 

 the blue clays of the Yaqui Valley to those of Bordeaux and Dax 

 was noted from the very first by Moore, Sowerby and Guppy. In 

 modern French nomenclature the fossiliferous marls of the Bor- 

 delais are placed in the Lower Neogene comprising a lower, 

 Aquitanian series typical at Leognan and Saucats and an upper, 

 Burdigalian series typical at St. Paul and Dax in the Adour 

 Valley. The Aquitanian was at one time regarded as Oligocene 

 but modern French stratigraphers place it in the Lower Miocene. 



The Dominican Orthaulax Formation is older than those of 

 Bordeaux and represents approximately the Rupelian Oligocene 

 of Europe and the Tampa silex beds and White Beach limestone 

 of Florida. It comes in just above the Vicksburg limestone. 



The Aphera Formation represents the Chipola marls of Flor- 

 ida and the Upper Aquitanian of the Bordelais. In modern 

 French nomenclature this is Lower Miocene. 



The Sconsia Formation would representing the overlying 

 Burdigalian and the cross-bedded sands above the Chipola marls 

 of Alum Bluff, Florida, also the Oak Grove sands of Florida. 

 Recent French authors classify the Burdigalian as Middle Mio- 

 cene. 



