136 



ox THE TOroaKAPHY AIS'D GEOLOGY 



terspei'scd with maii}^ large boulders of the syenites of the belt just south of the town 

 and through' which it flows a little further to the southeast. Its banks show jaspery 

 and clay slates cropping out in the bluffs. A couple of miles northeast of Jarabacoa 

 a gray claystone crops out, though the greater part of the rock is talcoid. In the 

 vicinity of the Yami River there are numerous quartz veins, and the river itself 

 yields a little gold, this being the only local it}^ in the neighborhood where the metal 

 has been found. After ci'ossing the Yami the trail climbs to the top of a high ridge 

 and follows along its summit through a beautiful open growth -of pine timber, and 

 over a bright red soil, almost all of the way in view of the Yalley of Yega. The 

 rocks are nearly everywhere a light-colored gi-eenish-gray talcose slate, often Avith 

 the soapy feel of steatite. In a few spots I found beds of sandstone interstratified 

 with the slates. These beds, nearly vertical, have a dip towards the valley near the 

 south end of the ridge. At the other extremity no dip could be made out with 

 certainty, although in more than one case I thought I could detect a lamination, 

 that seemed to point to a rather low di]) southward. At the northern end of the 

 ridge, just as the road commences its descent towards the Camu River, there is a 

 little seam of an asbestus-like mineral, which has not yet been submitted to the 

 examination of a competent mineralogist. Although the vein is hardly an inch 

 thick, the fibres, running longitudinally or a little obliquely, are some of them three 

 inches long. This is almost the only case where a mineral specimen of scientific 

 interest has been discovered during the progress of our work, unless the little alum 

 efflorescence at the mouth of the Jimenoa can be included in the list. At the foot 

 of this same ridge the rock changes into a brownish-black serpentine, with oblique 

 curved cross-fractures showing sufaces like " slicken-sides." This makes a part of 

 the bed of the river and changes into a little different color in the l)ank on the opposite 

 side. Here the cleavage surfaces are smeared, as it were, with a lighter color, while 

 fractures show the interior to be nearly black. A couple of miles of nearly level 

 ground in the valley, and two more crossings of the river, with occasional outci'ops 

 of light gray talcose slate, takes us to the village of Yega, spread out on a beautiful 

 plain on the verge of the Camu River. . 



The debris of the Camu is instructive as illustrating the geology of the nearly 

 inaccessil)le and enti)"ely unfrequented hills through which it flows. I found a black- 

 and-white coarse-grained syenite coming from the belt near Jarabacoa, very similar 

 to some from the. Jaina. Other pebbles of finer grain are not rare, and among the 

 usual varieties of metamorphic slates and sandstones, including those just mentioned 

 above, I found p'eces of a dai-k-green metamorphic conglomei'ate, with small pebbles, 

 almost identical with a bed in the Ocoa just south of Maniel. 



