1853.] HENEKEN SAN DOMINGO. 125 



Bed No, 1 is exposed only to the "j 

 depth of 10 feet, and cannot be traced 



beyond the main cliff owing to exten- 1 The fossils are disseminated 

 sive denudations. j throughout the shales. 



No. 2. About 20 feet thick. j 



No. 3. About 50 feet thick. J 



No. 4. About 90 feet thick ; composed of similar blue shale, with- 

 out fossils. 



No. 5. About 50 feet thick. Hard ferruginous bed. Fossils 

 decomposed. 



The upper surface of section No. 5 has evidently suffered de- 

 nudation. No. 6 is composed of shingle from older rocks, the size 

 of the boulders being from less than an inch to 18 inches in diameter. 

 This shingle is more or less tinged by the red oxide of iron, and has 

 a thickness of from 10 to 20 feet and upwards. 



No. 7 is a thick tufaceous limestone that covers the whole. 



In another cliff, a short distance to the north of Cercado, the lower 

 beds are hidden. No. 5, however, is here very conspicuous, but it is 

 more siliceous and gritty, and in some places excessively hard, and 

 some of its fossils are in better preservation, than at Cercado. 



Los Quemados (River Gurabo). — Beds of blue shale ; — dip N. by 

 E. Z 5°. 



The fossils from this place are identical with those of Postrero 

 and Cercado, merely offering some variety in the species. Though 

 the dip of the strata is here easterly, the same blue shale prevails, as 

 likewise the superior argillo-calcareous shale, but it is much thicker 

 than at Cercado, and is rather a dense mass of broken coral imbedded 

 in clayey matter. 



Hills of Samba (Tufaceous limestone). — The locality and forma- 

 tion of this range of hills have been already described. They are 

 capped by a deposit of tufaceous limestone with its peculiar fossils. 



The stratification of this tufaceous limestone is very obscure and 

 indistinct. I have never yet determined the dip satisfactorily, per- 

 haps from not meeting with it in favourable positions. It apparently 

 covers the inferior strata conformably, but I have reason to expect 

 that it will be found to be more horizontal. I suspect there has been 

 an oscillation and denudation to some extent, between the deposit of 

 the shale and the limestone, which future investigations may ascertain. 



On the summits of these hills the surface is crumbled and broken, 

 and no good specimens of organic remains are to be found ; the 

 remains of Mollusca and Corals are met with, but they are all in 

 a very decomposed state. It was only at the western extremity of 

 these hills (in the lee of the old current), where the limestone is 

 nearly in contact with the red sandstone, that good fossils were 

 obtained. Here I ascertained the dip to be W. Z 3°. 



The Grange. — This is an isolated table-mountain, the structure of 

 which for a long time I could not satisfactorily explain. After an 

 examination of the Samba Hills, however, it was suspected to be a 

 part of the same formation, and further investigations confirmed this 

 opinion. 



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