OF SAXTO noMTxr^o. ' 113 



towards Seybo and Samana Ba}- being lifted hardly a foiii'lli as high as those at the 

 head of the Yaqiii River and its upper branches. 



Both this chain and the smaller one of Samana furnish us with excellent keys to 

 the dates of their upheaval ; Samana being simply a repetition on a small scale, as has 

 already been said, of the larger Island. Santo Domingo probably first made its 

 appearance above the water either during the era of the white chalk of Europe, the 

 green sand beds of ]S^ew Jersey, or in the Eocene period. It then consisted of this 

 central chain, probal)ly extending out to the whole length of the present northern 

 peninsula of Hayti, accompanied by a group of smaller islands forming the southern 

 Haytien peninsula and possibly some of the other high lands of that region. To the 

 noi'theast lay Samana, a long low rocky islet, but slightly elevated above the sea, and 

 to the south of it, a little archipelago, which now constitutes the hills of Seybo. 

 During the Miocene period these islands were fringed with coral reefs, the fragmen- 

 tary remains of which still exist as patches of limestone, lying now as horizontally, 

 as when they Avere deposited on the upturned edges of the Cretaceous slates. The 

 elevating force had not ceased to act, and at the end of the Miocene, after having 

 been probably succeeded by a period of subsidence during that era, it was resumed 

 and has lifted the latter formation horizontally 200 feet in the middle of the Santiago 

 Valley, about 300 to 400 in the hills south of Samana Bay, and still higher in the 

 foot hills of the range at Cevico and west of the Upper Yaqui. In the latter case 

 the sandstone beds of the Miocene are highly uptilted. But these upheaving forces, 

 while they acted so gentl}'^ on this occasion at Samana, in the main range and in the 

 adjoining Valley of Santiago, were much more violent a little further north, and 

 pushed up the formation along a line an hundred miles long, in some cases to a 

 height of 3000 feet or more, making the Monte Cristi chain where, nntil the end of 

 the Miocene, had been a level sea-bottom covered with white calcareous mud. 



The Pico del Yaqui, more commonly called El Rucillo by the people living near 

 its base, is at the same time one of the highest, if not the highest point on the Island, 

 one of the most central and an excellent starting point for our detailed descrij)tion of 

 geological features of the range. As stated in a previous chapter, its height is per- 

 haps a little over 9000 feet. It is a sharp ridge, very nai-row, but about a mile long, 

 a broad rounded curve, with a little sharp peak at its eastern end, lower than the top 

 of the curve. From the eastern end a long ridge runs to the eastward continuing 

 the water-shed and separating the waters which run north from those which empty 

 into the l^eybo River. From the same point a long spur runs out to the north, on 

 l)oth sides of which rise streams which unite to forui the longest branch of the Yaqui 

 A. p. S. — VOL. XV. 2c. 



