OF SANTO DOMINGO. 



149 



I could obtain no apparent dip that was not immediately contradicted l)y another as 

 well marked in another direction. The metamorphic action has almost complete!}^ 

 destroyed the stratification of the rocks. 



My pei'sonal explorations did not continue beyond this point eastward, but Mr. 

 Kunnebaum, who explored the outside of the i"ange, both on the coast and inland 

 (there are no roads across it except a few pig-hunter's trails), reported that no 

 changes occur. The same slates, with ill-defined bedding, occasional pieces of sand- 

 stone in the creeks and a little barren quartz, make this region a mere repetition of 

 that already described ; while the absolute absence of inhabitants and means of com- 

 munication render the obtaining of any information extremely difiicuit. 



CHAPTER IX. ' . 



GEOLOGY OF THE N0IIT1IE31N VALLEYS AND FOOT-HILLS OF THE MAIN CHAIN. 



The preceding chapter has been devoted, with one or two trifling exceptions, to a 

 description at the same time of the central Sieri-a, and to the rocks which from being 

 almost exclusively confined to it, I called provisionally the "Sierra Group." Except 

 part of the Peninsula of Samana, and a little outline near Puerto Plata, all of that 

 portion of the Island l3nng north of these mountains is made up of the two members 

 of the Tertiary described in preceding chapters. The long depression of the Cibao, 

 including the valleys of the Yaqui on the west and the Yuma on the east, is under- 

 laid by the older or Miocene group, which also constitutes the Monte Cristi range, 

 while the more modern coast formation simply borders the sea as its name imj^lies. 



The base of the Miocene at Tabei'a has been already described, consisting of 

 heavy beds of a coarse gray sandstone, highly uptilted and lying on the flanks of the 

 Cretaceous slates at Tabei'a, on the Yaqui south of Santiago. From there an excel- 

 lent natui"al section extends to the Angostura (or narrows) of the Yaqui near Santi- 

 ago, the dip becoming gradually lower until at that place it falls as low as 5° to the 

 north. The dark sandstones dip undei", and the beds at Angostura are higher in the 

 series; being made up of dark-colored shales, with seams of a dark-bluish conglome-~ 

 rate full of fossils from which 1 extracted with great ditficulty some i'ew species, all 

 identical with those from the blue shale. This conglomerate is a very shallow water 

 or perhaps beach deposit, being made up of rounded pebbles, broken shells and con- 



A. p. R. VOL. XV. 2l. 



