or SANTO DOMINGO. 



173 



Fi-om old Cape Frances the extreme northeastern corner of this range, which ] 

 have never visited, Mr. Pennell brought me a rock identical with that which occurs 

 on the point of Cape Cabi'on, and which indicates the probable existence of the Sierra 

 group in that neighborhood. Some of the Sierra limestones of Samana are of a pecu- 

 liar dark blue, semi-crystalline in structure, like an imperfect marble. At both of 

 these places such a rock has been broken down into small splinters and angular frag- 

 ments and re-cemented by a yellowish stalactitic deposit, making a coarse breccia 

 with numerous cavities.. The resemblance between specimens from these two locali- 

 ties is perfect, and since the blue rock from which the fragments ai'e derived at Cape 

 Cabron is in place, the deposit being a sort of talus, I infer that a similar condition 

 of aifairs exist at Cape Fi-ances. How much of this part of the range may consist 

 of this formation we do not know. This is one of the problems for future geologists 

 to solve. Mr. Pennell found it at all of the points from Punta Laguna Gringrisa to 

 Cape Amaras. It must be understood that all of this region goes by the name of 

 " Old Cape Frances," which is not applied to any one particular point. From the 

 topographical structure, and fi'om the fact of the rock being only found on this one 

 spur, it is probable that it will not be found to extend much beyond a line drawn 

 from Cape Amaras to the north of the San Juan. But he is not to be envied who 

 shall settle the question. The interior region is entirely uninhabited, there is not a 

 road or trail through it, and it is practially impenetrable. It consists of a broad mass 

 of low, heavily wooded hills, never visited except by a few pig-hunters. 



CHAPTER XI. 



GEOLOGY OF SAMANA. 



In studying the geology of Samana we find a repetition of all the phenomena of 

 the larger island, with the exception of the eruptive rocks. I call it island rather than 

 peninsula since it is separated from the mainland by the Gran Estero, formerly a 

 navigable stream, now partially closed. Cretaceous rocks higlily metamorphosed 

 and uptilted ; Miocene Tertiary deposited on their edges or flanks, these ele^•ated 

 horizontally almost to the highest summits of the hills, and the whole flanked by 

 Post Pliocene coast foi'mations consisting of limestones and gravels constitute the 

 summary of the geology. N"o syenites whatever have been found either in place or 

 even in the coast gravels. 



A. r. s. — yoi>. XV. 2k. 



