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OK THE TOPOGEAPIIY AND GEOLOGY 



From the Avest end of the ridge of the Riicillo, there starts out ii spur as heavy 

 as the parent mountain. At a distance of ahont ten miles from the main chain it 

 cnhninates in a noble peak, Loma Joca, called on Schombnrgk's map "The Peak." 

 This mountain sends out a radiating series of ridges which extend far out towards 

 the valley, and give rise to most of the branches of the Bao River, the principal of 

 which are the Guanajuma,"^ the Baguati, or Boguaci, and the Jagua. Like the main 

 ridge, all of the region of Loma J oca is syenitic, the rock extending on the Baguati 

 to within a dozen miles of its confluence with the Jagua, At this point on the 

 former stream Mr. Speare collected a peculiar coarse-grained dark-colored syenite, 

 with small scales of a shining mineral which seems to be mica. Almost immediately 

 north of this spot, the Cretaceous beds appear as dark-colored heavy-bedded clay 

 shales. On the same line of strike on the Jagua, about ten miles from its mouth, 

 the rock is somewhat calcareous, and varies in color from gray to greenish, while 

 nearly in the same line, perhaps a little farther north on the Bao, the shale is black 

 and earthy, alternating with beds of lighter color, and although not specially cal- 

 careous, containing streams of calc-spar. The amount of disturbance to which the 

 rocks of this vicinity have been subjected is so great, that while a general tendency 

 to a nearly east and west strike can be made out, the di]) is practically vertical. 

 Occasionally a lower incline may be observed, but it is extremely local, and it is as 

 often in one direction as another. , 



Approaching San Jose de las Matas, the rock changes its character to a gravelly 

 sandstone, often full of pebbles, and occasionally giving way to distinct beds of 

 conglomerate. Hei'e almost all the beds are more or less red, stained by oxide of 

 ii'on ; the soil is a loose red gravel, unusually barren, and the surface is clothed with 

 grass and occasionally a patch of pine forest, interspersed with the " guano " palm, a 

 slender little fan-palm, grow ing twenty feet high. The barren soil, w ith its consequent 

 pine and palm-gi'owth, seems to follow closely the metamorphic slates, from San 

 Jose to the west. Its barrenness is due in part to the scarcity of rain. In the 

 western })art of the valley showers are rare, and when they do fall are less violent 

 than in its eastern end. South of San Jose the country, as far as we penetrated, was 

 made up of slates — red, brown, black — vertical or dipi)ing slightly to either side of 

 the perpendicular. In the side of the hill below San Jose, there is a clilf of dark 

 reddish-brown sandy shale standing almost vertically, and with broad surfaces 

 cleared clean in the line of stratih cation. The town itself is very peculiarly and 

 beautifully situated. It occupies a little basin, nearly level, surrounded by rolling 



* This must not be confounded with the Guanajuma which rises iu the Pico Iliihio and empties into the Amina. 

 Much conl'usion arises from the constant repetition of local names. 



