GEOLOGY. 299 



ON THE GEOLOGY OF HAYTI. 



At a recent meeting of the Boston Society of Natural History, Dr. D. F. 

 Wineland read a paper on some points of the geology of Hayti, the result of 

 personal examinations. 



The northern shore of the south-western neck of Hayti is mostly an iron- 

 bound coast. There are but few small sandy bays, which serve as landing- 

 places for the fishing-boats, and near them are generally found huts of fish- 

 ermen, or a small village. 



The rock which bounds all the rest of the coast is a hard, brittle limestone, 

 formed very generally of a conglomeration of madrepores and other corals, 

 as Astragie, Mffiandrina?, Milleporce, etc., and of various kinds of shells, 

 cemented with a mass of smaller and formless lime particles, the powdered 

 particles of the same corals and shells. This rock is full of pores and 

 roundish cavities, with sharp edges, perhaps the places where softer shells 

 or fragments of coral have been washed out by the erosion or attrition of 

 the water, or knocked out by corals, thrown up in the stormy winter season 

 of the furious north wind. The species of corals and shells which enter into 

 the composition of this rock, I found nearly all alive in the adjoining sea. 

 Some of them, however, have disappeared from among the living; others 

 are dying out, and are now very rarely found, though common in the earlier 

 portions of the present period; for they exist in great quantities in the rock 

 at the depth of a few feet. Such animal remains enclosed in rock, yet 

 belonging to species now living, or to species now extinct, but which lived 

 in the earlier ages of this period, together with species now living, we are 

 accustomed to call modern fossils. They are the more interesting because 

 they show how, without any remarkable revolution of our globe, certain 

 species of animals gradually die out. 



The same rock, composed of modern fossils and their detritus, I found in 

 the interior mountain regions of the island, about thirty miles from the sea- 

 shore, and at a height, as I should judge, of at least one thousand feet above 

 the present level of the sea. Indeed, the whole first, that is, northernmost, 

 ridge of mountains which runs along that northern sea-shore of Hayti, from 

 east to west, is crowned with large layers or broken masses of this same 

 kind of rock, which being, as stated above, a formation of the present geo- 

 logical period, goes far to show that this whole ridge has been raised in this 

 present period. Thus the existence of the greater part, and the configura- 

 tion of the whole of the southwestern neck of the island of Hayti, is of com- 

 paratively recent origin. 



Two questions at once suggest themselves here, whether the formation of the 

 same rock, and whether the elevation of the land, are going on at the present time. 

 That the former, the formation of the limestone rock, is really in progress 

 at the present day, seems to be evident in some places, where the whole bot- 

 tom of the sea near the shore, at a depth of from one to five and six feet 

 below low-water mark, is, as it were, a flat pavement of the same kind of 

 rock. Crust-building corals, as Porites, Mceandrinas, Siderastrceas, etc., live 

 npon it, and in the interstices of these are thrown up from below dead 

 shells, broken Millepores, Madrepores, and Astrosans. By the powerful 

 action of the waves on the shallow bottom, these remains are broken and 

 ground upon each other, and their form is lost. 



The lime powder which results from this pulverizing action furnishes the 

 cement which fills the shells and unites the pieces into one solid mass, 



