215 GEOLOGY OF THE PROVINCES OF BARAHONA AND AZUA. 



accompanying section. Higher beds of the same formation outcrop in the 

 lowlands and hills north of Cerros de Sal. Thick beds of clay and sand- 

 stone were also noted, but they are not listed in the section. Beds of 

 bituminous limestone occur in the series near Angostura. 



Condensed stratigraphic section of Cerros de Sal formation. 



7. Sandy shale, poorly exposed, alternating with calcareous, fos- xhiokness 

 siliferous sandstone that forms low ridges north of Cerros de i n meters. 

 Sal 300 



6. Cross-bedded sandstone, unconsolidated, alternating with 



gypseous shale; strike N. 70° NE 150 



5. Sandy clay beds, light-olive color, with embedded corals at two 

 horizons (station 8574, list of fossils on pp. 163-164) ; strike 

 about N. 70° W., dip vertical 400 



4. Sandy clay beds of various colors, with several shell beds, com- 

 posed of oysters, areas, and other fossils (station 8572, list of 

 fossils on pp. 163-164); also with thin layers of impure 

 earthy lignite 170 



3. Sandstone, sandy shale, and thin layers of pinkish fossiliferous 



limestone, which form the north face of the high ridge 150 



2. Gypsum in thick, massive, white, finely crystalline layers, 

 alternating with thinner layers of green gypseous shales and 

 with beds of coarsely crystalline salt; gypseous shales in 

 upper part 700 



1. Red and yellow sandy clay and sandstone 100+ 



Gypsum interstratified with beds of salt and shale forms the upper 

 part of the high ridge of the Cerros de Sal (altitude about 200 meters). 

 These beds are underlain on the southwest side of the ridge by shaly 

 reddish-brown clays. In the valley on the northeast side of the ridge 

 the gypseous strata are overlain by a few thin beds of pink limestone, 

 above which lie shale and sandstone alternating with variegated clays, 

 the whole loosely cemented or with only a few beds of calcareous sand- 

 stone, which is sufficiently indurated to form low hogback ridges. The 

 mollusks and corals, which are abundant in the strata, indicate that the 

 formation is late Miocene. 



THE SALT DEPOSITS. 



The salt deposits occur on the north side of Cerros de Sal near the top. 

 They are the property of the communes of Las Salinas and Angostura. 

 The people of Las Salinas work in the excavations known as the Carrera del 

 Potro, Manuel Perez, and La Partilla and several smaller excavations. 

 Work is usually done at only one locality at a time. The workings of the 

 inhabitants of Angostura near the western end of Cerros de Sal were not 

 examined. 



The salt deposits are in the upper part of the gypseous beds of the Cerros 

 de Sal formation. The thickness assigned to this member — 700 meters — is 

 a minimum one, and more detailed work may show that it is much greater. 

 The upper part of the member contains a larger proportion of shale than the 



