GEOLOGY OF THE PROVINCE OF SAMANA. 183 



in the mountains. On the south slope of the mountains hard, moderately 

 schistose gray limestone is the most common rock of the basal complex. 

 The strike of the schistosity is in general parallel to the direction of the 

 trend of the peninsula, but no bedding planes or fossils were observed in 

 any of the metamorphic rocks. The age of these rocks is not known, but 

 they probably are of the same age (Upper Cretaceous or older) as some of 

 the rocks of the basal complex in the Cordillera Central. Evidences of 

 normal faulting were observed along the southern base of the mountains. 

 On the south shore of the bay the mountains east of Sabana de la Mar 

 appear to be composed largely of sedimentary schists cut by basic dikes. 

 At Las Cafiitas the schists are highly metamorphosed sandstone, sandy 

 shale, and conglomerate. The bedding strikes N. 60°-80° E. and dips 

 15°-40° SE., but the schistosity strikes N. 40° W. and dips 70° SW. The 

 schists are cut by dikes of finely crystalline greenish lamprophyre that 

 contains bunches of epidote. The dikes are vertical, are 30 to 60 centi- 

 meters wide, and strike northeast. Banding that strikes N. 10° W. and 

 dips 60° NE. was observed in one of the dikes. 



EARLY TERTIARY LIMESTONE CONGLOMERATE. 



A heavy, rudely bedded conglomerate is exposed in stream valleys and 

 on some of the mountain spurs on the south slope of the peninsula west of 

 Samana. The pebbles, which are oval and usually flat, consist almost ex- 

 clusively of the schistose limestone of the basal complex. They average 

 15 to 18 centimeters long, 8 centimeters wide, and 4 centimeters thick. 

 The matrix is a yellowish calcareous cement. 



The conglomerate has been folded, but, though thoroughly consolidated, 

 it has not been greatly metamorphosed. Its age is probably early Ter- 

 tiary, for it rests unconformably on the basal complex and is overlain 

 unconformably by deposits of supposedly late Tertiary age. 



OLIGOCENE OR MIOCENE LIMESTONE. 



Hard yellow limestone crops out in the upper part of Sierra Prieta, a 

 small hill 45 to 60 meters above sea level at the foot of Loma Jackson, 

 about 18 kilometers northwest of Sanchez. At the base of the hills lie loose 

 blocks of hard conglomerate composed of limestone pebbles like those that 

 form the conglomerate already described. The corals collected from the 

 limestone (station 8606, p. Ill) are of late Oligocene or early Miocene age. 



Yellow foraminiferal limestone was found in talus at the foot of Loma 

 Jackson. Similar rock, which has been brought from Arenosa, a station 

 on the Ferrocarril de Santiago y Samana, in the Province of Pacificador, 

 about 30 kilometers west of Sanchez, is used in a retaining wall near the 

 railroad station at Sanchez. This rock is probably of Miocene age. 



Limestone also occurs in the plateau at the east end of the peninsula. 

 The interior of the peninsula was not examined, but the flat and even sky 



