GEOLOGY OF THE PROVINCES OF BARAHONA AND AZUA. 205 



side of the river leads over a steeply sloping mountain side at an altitude 

 of about 1,100 meters. 



The age of this series of sedimentary rocks is not known, as no fossils 

 were found in it. The rocks are similar in lithology to sandy beds seen 

 near Bani, which are probably of Eocene age. The regional alteration 

 may have been caused by the intrusion of the large masses of quartz 

 diorite that cover much of the region east of Restauracion. 



The trail from Constanza southward descends the steep side of Loma 

 Higiiela or Chingiiela, the top of which probably reaches an altitude of 

 1,500 meters above sea level, and follows the narrow gorge of Rio del Medio 

 down to Arroyo el Gorbano, where it begins to ascend Loma la Fortuna, 

 making a steady, steep climb to an altitude of about 1,000 meters above 

 sea level, beyond which it follows the undulating crest of the mountain to 

 Las Cafiitas, a settlement scattered over the side of the mountain at an 

 altitude of some 1,100 meters above sea level. 



At Las Cafiitas a splendid view can be had of the great bulk of Monte 

 Culo de Maco, towering above the canyon of Rio del Medio. This moun- 

 tain, which is said to be as high as the more famous Monte Tina, is probably 

 one of the highest in the island. The mountain falls off steeply at its 

 north end, but its southern or southwestern slope is even and gentle, ap- 

 pearing, as seen from a distance, like a dip slope. From the southwest 

 side of Loma la Fortuna one can look out across the valleys of Rio Yaque 

 del Sur and Rio de las Cuevas. 



Beyond the ford of Rio del Medio at Limon the trail leads across Loma 

 la Laguna (altitude about 950 meters above sea level) and descends 

 gradually to Rio de las Cuevas, down the boulder-strewn bed of which it 

 extends to Tiibano. 



The mountains between Constanza and Las Cafiitas are carved out of 

 a great massif of serpentine. Their slopes are steep but usually not pre- 

 cipitous, and they are easy to climb. They are clothed for the most part 

 with an open pine forest and a thin carpet of grass. Near the foot of 

 Loma las Cafiitas, at an altitude of about 925 meters and about 8 kilo- 

 meters from the village of Las Cafiitas, a quartz vein that contains copper 

 ore cuts the serpentine. The width of the vein is variable but where seen 

 does not exceed 2 meters. Several of the common copper minerals, in- 

 cluding chalcocite, chalcopyrite, and bornite and their oxidized products, 

 were recognized. 



About 1 kilometer beyond the outcrop of this vein and about 75 meters 

 lower a bed of hard blue limestone abuts against the mountains of serpen- 

 tine, from which it is evidently separated by a fault. This bed is probably 

 a mass that has been separated from the main body of limestones of the 

 older series, chiefly of Eocene age, by block faulting, but as no fossils 



