PALEOZOIC UNDIVIDED. 347 



In the interior of the mountains, especially in the western two-thirds, the disturbance has 

 been greatest, and the reason appears in the existence of great masses of eruptive rock which 

 have pushed up the slates, broken them, and in some cases penetrated them by dikes to a 

 distance of several nules from the parent mass. In some cases pieces of the wall rock are found 

 embedded in the syenite; and pebbles one-half syenite and the other half j'aspery are not rare. 



In its original state this group of beds seems to have consisted of a series of clay shales, 

 t hinl y bedded, others more heavily bedded and with layers of sandstone, conglomerate, lime- 

 stone, and heavy-bedded sandstones. The changes produced in these rocks by metamorphism 

 are almost infinite. On the Ocoa River the shales are so nearly unaltered that I have repeatedly 

 searched in this region in hopes of finding fossils. In the canyon of the river they are gray and 

 friable, with an occasional bed of sandstone; farther south they are red and give rise to numerous 

 salt springs; still farther south they contain more numerous beds of sandstone and are brown 

 and more sandy in texture. These same shales are modified at Recol into a granular greenish- 

 black material resembling an impure serpentine, while on the Nigua they appear as green, gray, 

 or brown jaspers with broad conchoidal fractures, gradually changing again within a few miles 

 to a more serpentinoid form, to reappear as the same jasper on the Jaina and to again change, 

 on the Upper Jaina and in nearly all the mountains eastward, into a whitish rock, more or less 

 talcoid and profusely stained with iron. On the north side of the island the modifications of 

 the shale are just as great. The sandstones also undergo an equal number of variations, 

 appearing of all colors from black or dark-gray sandrock to a white granular quartzite. In 

 short, nearly every color is represented, and naturally all degrees of texture, from the coarse 

 conglomerate of San Jose de las Matas, or Maniel, to the shale above described. In one place 

 only did I find siliceous segregations likethe chalk flints, or more probably, hke the Corniferous 

 Umestones of the New York geologists. In the hill just west of Bani the rock is a Hmestone, 

 and in it are numerous streaks, lying in the plane of stratification, of a hght-brownish limestone, 

 very tough and breaking with an irregular fracture. Near the base of the series, apparently, 

 are strata of conglomerate, made up of pebbles very similar to those of the surrounding beds. 

 These pebbles seem to have been brought from long distances, since they are almost invariably 

 rounded by attrition. They are largest on the upper Ocoa, near Maniel, and on the north flat 

 of the range near San Jose de las Matas, but at these points they are rarely more than a few 

 inches in diameter. I have endeavored in vain to find the probable source of these pebbles. 

 They are certainly not from the adjoining beds, although hthological researches were not wanting. 

 They are not derived from any deposit encountered by us on the island, since the conglomerate 

 strata extend nearly, if not entirely, to the base of the stratified rocks. It is not probable that 

 further examination to the westward, in the yet unknown portions adjoining Haiti, or lying 

 within its borders, will develop their origin, since such a discovery would be foretold by increase 

 in the size and angularity of the pebbles in that direction. They must therefore have been 

 derived from some land then existing, most probably to the north or northwest of the present 

 island, but now submerged or destroyed. The conglomerate is variable in its character and the 

 changes take place over comparatively limited areas. On the north side it is almost always 

 cemented by a coarse-grained red sand, the surfaces of the contained pebbles being stained by 

 the ferruginous nature of the matrix. This is the rule where the metamorphosis is not very 

 perfect. In one place, west of San Jose, the whole mass is rendered nearly homogeneous in 

 texture, the fracture crossing matrix and pebbles alike. In another, on the Mao River, the 

 whole is changed to a dark olive-green, the coloring matter having stained even the interior of 

 the pebbles.. On the Ocoa some of the conglomerate is cemented by lime instead of sand, and 

 in this case the pebbles are not so numerous as to be always in contact. This pecuharity 

 gradually changes to the eastward, so that the conglomerate is represented on the Nigua by a 

 group of beds, in part pure limestone, in part an impure limestone, containing occasional pebbles. 

 This last is the stratum from which fossils were obtained. 



Statements relating to the discovery of fossils of Cretaceous age are given in 

 Chapter XV (pp. 642-643). 



