96 



ON THE TOPOGRAPHY AND GEOLOGY 



Fossils arc not regularly distributed either vertically or laterally, but seen to occur 

 in colonies. The blue shale bluff under the city of Santiago, sixty feet high from the 

 level of the river, does not show a single streak where they are ever abundant enough 

 to repay the trouble of hunting, although isolated shells occur throughout. At Punal 

 but a few miles off near the Rio Yerde shells and corals abound. The same irregu- 

 larity exists throughout, and although there is but little change in the species of the 

 mollusca in their vertical range, there is a marked difference between the eastern and 

 western ends of the basin. Shells that are absent or scarce on the Verde are connnon 

 on the Gurato and westward, and lyice versa. The corals found in the shale are almost 

 always of the cu]) forms, while the massive corals are almost exclusively confined to 

 the upper beds and are particularly abundant on the north flanks of the Samba hills. 

 In all the shale beds and to the extreme top of the series foraminifera occur, and in 

 some places are found in great numbers. They are not very numei'ous in species, 

 probably not exceeding half a dozen. The Orhitoides ranges throughout all the 

 strata and is not only found wherever any other fossil occurs but is often, especially 

 in the higher beds the only recognizable organic remains. It has more than once 

 proven of great value to me in distinguishing these limestones from the overlying 

 Post Pliocene calcareous beds. 



With one or two small exceptions all these rocks ai*e entirely unaltei'cd. On the 

 southern limit in contact, or nearly so with the underlying cretaceous in the vicinity 

 of the Bao River and on the Yaqui, the coarse sandstones are slightly modified, though 

 still retaining their stratification and mechanical structure unchanged. On the Yaqui 

 at Tabera this rock is highly uptilted and slightly contorted as will be seen by refer- 



ence to the description of the locality. Also in the northern range a similar sli^m 

 metamorphism occurs southeast of Puerto Plata. 



The geological age of the West Indian Tertiaries has been so thoroughly and ably 

 discussed, and by such competent authorities that it might seem unnecessary for me 

 to reopen the subject. J. C. Moore,'^* Geo. B. Sowerly,t Dr. P. M, Duncan,J R. J. 

 L. Guppy,§ Robert Etheridge,|| and Sir Robert Schomburgk,^ have all contributed to 

 the general fund of our knowledge, and have unanimously agreed in placing the 



* Quart. Jour. Geol. Soc, Vol. IX., p. 129, and previously in 1850, loc. cit., p. 39. 

 \ Loc. cit., p. 44, et seq. 



t Quart. Jour., Vol. XIX., p. 40C, and Vol. XX., p. 20. 

 § Id., Vol. XXII., p. 281, ct seq. 



II Geological Survey Report, Trinidad, App. J., p. 161, and Geological Survey Report, Jamaica, App. V., p. 311. 



Hist, of Barbadoes, p. 531, et seq. See also Nelson in the Bermudas; Trans. Geol. Soc, 3 Ser., Vol. V., part 

 1, p. 103 ; and on the Bahamas, Quart. Jour. Geol. Soc, Vol. IX., p. 200. 



