or SANTO DOMINGO. 



169 



bluffs of from forty to sixty feet high, in some cases forming bold headlands. ISTo- 

 wliere is it very wide, and the encroachment of the sea is slowly but surely under- 

 mining and wearing away the little remainder. I ti'aced it as far as I went, to Isabella ; 

 but from the contour of the surface beyond that, as seen from that point, I do not 

 think it makes a. notable feature in the geology. 



While the Alta Mira Pass crosses the head of the Isabella River and skirts around 

 the west side of Mount Diego Campo, the Palo Quemado Pass running around the ' 

 east side of the same mountain, crosses the upper part of the Yasica Kiver. The 

 upper part of the yellow shales, occasionally calcareous, are seen in the valley before 

 reaching the hills, rolling with a general east and west strike and dipping north or 

 south indifferently. The trail runs up a long spur of the Palo Quemado mountain, 

 showing first the yellow shales with a little limestone dipping towards the valley and 

 exhibiting their edges on the crest of the ridge. At the summit of Palo Quemado 

 Mountain a little yellowish limestone remains ; but on descending on the north side 

 the rocks are encountered in a regularly descending series to the bed of the Yasica 

 River, here a stream of half a foot deep and twenty to thirty feet wide. In its bed 

 gray shales Avith a little sandstone form nearly flat ledges, with little dip in any 

 direction. Mixed with the pebbles of these sandstones are very numerous boulders, 

 some of them over a foot in diameter, of a tough coarse-gi'ained syenite, undistinguish- 

 able in any of its characters from similar rock in the Cibao range. This syenite was 

 not seen here in place, and I might have been tempted to have considered it as 

 derived secondarily from a conglomerate had I not seen it elsewhere forming large 

 dykes cutting through the Tertiary rocks. The large size of the boulders and their 

 great number, not less than the comparatively short course of the river, prove that 

 the dyke fi'om which they were derived is not far ofi'. A little settlement, called 

 Yasica Arriba, of four or five houses occupies a pretty little open spot, comparatively 

 level, bordering the river. The people, as is usual among these mountaineers, earn a 

 scanty livelihood from the herds of half-wild pigs that roam through the woods ; a 

 not very remunerative occupation, but one that involves plenty of healthy out-of-door 

 exercise in capturing their property when they desire to avail themselves of it. From 

 the crossing of the Yasica the trail crosses another high ridge cpmposed of similar 

 shales and sandstones with a constant east and "west strike and with a low but 

 marked northern dip. Towards the northern base the rocks become entirel}^ sand- 

 stone and show evident marks of metamorphism, though not so strong as those near 

 Puerto Plata. About four miles from the town I found a brown sandstone Avith 

 minute specks of mica, as it were an inlermediate stage between the unaltered sand- 

 A. r. s. — VOL. XV. 2q, 



