GEOLOGY AND GEOLOGIC HISTORY. 63 



to Altamira (station 8713); at Yaroa village, about 17 kilometers north of 

 Pena (station 8719); at Las Cacaos, north of Pena, near the head of Rio 

 Licey (station 8740); on Las Lavas Creek, above Las Lagunas, on the 

 Santiago-Altamira trail (station 8704); and probably at Las Lagunas 

 (station 8703). Lists of the fossils from these localities are given on 

 pages 107, 108, 111. 



In the Province of Puerto Plata deposits of probably Oligocene age were 

 found on the north slope of Monte Isabel de Torres at an altitude of about 

 320 meters (station 8675) . The fossils collected at this locality are listed 

 on page 111. They resemble in their stratigraphic affinities the fauna 

 of the Tabera formation. 



Limestone containing fossils of middle Oligocene age was found on the 

 south side, in the Province of Azua, at at least five localities. The [precise 

 localities for the fossils and their names are given on pages 108-109. 



At the east end of the Sierra de Neiba limestone containing Foraminifera 

 that are probably of Oligocene age was collected on the right bank of Rio 

 Yaque del Sur opposite Bastia, about 1.6 kilometers northwest of La 

 Trinchera. The Foraminifera are listed on page 112 (station 8569). 



Cevicos Limestone. 



The name Cevicos limestone is taken from the village of Cevicos, near 

 the east end of the Province of La Vega. The formation has been ex- 

 plored only along the trails leading from Cotui eastward to Cevicos and 

 from Cevicos northward to Villa Rivas. On the trail from Cotui the forma- 

 tion was first seen in Arroyo Blanco, at the eastern foot of Loma de los 

 Palos, from which it extends, most of the way under cover, to Cevicos. 

 It was traced several kilometers north of Cevicos but disappears beneath a 

 thick reef-coral limestone, supposed to be of Miocene age, which forms the 

 rugged plateau bordering the Vega Real. (See page 30). 



The Cevicos limestone is yellow or cream-colored, more or less argilla- 

 ceous, and in places nodular. It contains many fossils, but few of them 

 are sufficiently well preserved to be identified. A species of Orthaulax 

 (0. aguadillensis) is abundant at Arroyo Blanco but was not seen elsewhere. 

 This species, as well as two echinoids, Clypeaster concavus Cotteau and 

 Brissopsis antillarum Cotteau, correlates the Cevicos limestone closely 

 with the fauna of the Anguilla formation of Anguilla, which, according to 

 current American usage, is considered uppermost Oligocene. 



Although it is here classified as Oligocene, the Cevicos limestone as well 

 as the Anguilla formation of Anguilla and the Emperador limestone of 

 Panama, with which it is tentatively correlated, may ultimately be referred 

 to the lower Miocene. The coral faunas of these formations, according to 

 Vaughan, are in some respects similar to Miocene faunas and can be sepa- 

 rated from them only with difficulty. In its lithology and structure also 

 the Cevicos limestone resembles the formations of the Yaque group much 



