176 



ON THE TOLMXniAPHY AND GEOLOGY 



four or five miles northwest of Santa Barbara a bed of white limestone of the same 

 age occurs. On descending from the top of the pass and entering the lower hills, 

 they are found to be composed of horizontal strata of gravel, apparently of the 

 coast formation, made np entirely of debris of the limestones, mica slates and tal- 

 cose slates which form the higher range. This gravel, like the Miocene to the west 

 of it, makes a belt adjoining the coast and extends about a dozen miles east and west, 

 foi'ming in some places high bliifl's with nearly vertical faces overhanging the bay. 

 It also constitntes the little islands that lie in the neighborhood of Santa Barbara. 

 Althongh a comparatively modern formation it is so solid as almost to merit the 

 name of a conglomerate ; and it resists the encroachment of the waves almost as 

 well as the neighboring points of limerock. To the west it extends as far as Los 

 Corosos, where it first appears as a steep hill. 



Between the San Juan and the Arroyo Salado, on the Arroyo Canas, in addition 

 to the limestone so common in this region, there is a pecnliar yellowish-gray talcose 

 slate. It is very fissile and is nearly pure talc. The deposit is quite limited and is 

 almost the only one in Samana. In the same neighborhood, on the Rio Pito, a branch 

 of the San Juan, bnt further sonth, there is a gray mica slate cut np by numerous 

 milky-white quartz veins. Both these rocks have low northern dips. 



The gravel beds continue for two miles east of Santa Barbara, where the lime- 

 stones and mica slates of the interior first come down to the coast. At this point 

 occurs the curious mixture of lime with mica referred to above. A series of gray 

 limestones crop out on the beach, striking about due east and west, and dipping north 

 from 65° to 80°. Interstratified with these are beds of mica slate ; but one stratum 

 of two or three feet thick particularly struck my attention. On examining a block 

 of it on the beach, fallen from the bed, I found one side pure limestone ; further in 

 there were little scales of mica regularly disposed in layers, the lines of deposition ; 

 and this mineral became regularly more abundant until the opposite side of the same 

 block was a pure mica slate, showing no sign of lime to the eye. East of this point 

 the rocks become vertical; still further east, a high northern dip returns, but at La 

 Flecha they fall almost to a horizontal and become nu)re micaceous. ]^ear Punta 

 Cacao, the rock is a silver-gray very fissile mica slate. Similar rocks and some clay 

 slates continue pa st Punta Balandra, where with a northeast dip they disappear undei- 

 the horizontal Tertiary which forms a little basin back of Puerto Frances. This is 

 an isolated deposit of horizontal rocks, limestone and sandstone, always white, al- 

 though in some places, the former has a pinkish tinge. The omnipresent Orbitoides 

 ibrtunately appear in some places and thus saves us from the uncertainty that might 



