OF SANTO DOMIJSTGO. 



m 



hang around the age of so exceptional a group of rocks. Until its discovery, I was 

 incHned to consider the beds as belonging to the coast limestone. This basin extends 

 from Point Grapin to the base of Cape Samana, and runs back forming almost a 

 plain to within a couple of miles of Rincon Bay. Here it abuts against the edges of 

 the Cretaceous shales which are elevated nearly vertically and which are represented 

 in this ridge by brown and gray clay slates, dipping at very high angles to the north- 

 west. These slates run out to the eastward and constitute the bold headland of Cape 

 Samana ; while Cape Cabron, running north on the west side of Rincon Bay is made 

 up of the mica slates and dark, blue limestones such as have been described from the 

 San Juan and Limon. On Cape Cabron, on the trail crossing the ridge, the dark 

 blue limestone is broken into a coarse angular breccia and recemented by a yelloAvish 

 calcareous infiltration sometimes leaving cavities unfilled. I cannot determine 

 whether this is a recent deposit or whether it dates back as far as the coast limestone. 



Although the gravels about Santa Barbara have been referred to the "coast forma- 

 tion," I have detected no other locality of this group except a trifling little outline, 

 bordering the coast at and near Puerto Frances. Here it makes bluffs about twenty 

 to twenty-five feet high, worn into the most irregular forms by the action of the sea, 

 which beats against it with more than usual violence. The deposit is very small, ex- 

 tending a mile or two along the coast and pei'haps nowhere more than half a mile 

 inland. 



CHAPTER XII, 



GEOLOGY OF THE BEGION SOUTH OF THE MAIN BAKGE. 



The southern slope of the Island divides itself naturally into two distinct and well- 

 marked portions — the mountainous or hilly region and the plains. The latter extends 

 east from the vicinity of the Ozama and its tributaries, or more properly it may be 

 said to include all the country east of the Jaina, while the former comprises all to the 

 west of that river, including the region about the upper half of its course. 



Although the district east of the Jaina covei's an area of over 1,500 square mileSj 

 it fui'nishes but very few items of interest for the geologist. It has already been 

 described in the chapter on its topography as a plain, nearly level, or at most gently 

 I'olling, in part open grassy savanas varied by long lines of trees bordering the water- 

 courses, or in clumps scattered over their smface and covering every depression. 



A. p. S. VOL. XV. 2s. 



