HILL: GEOLOGY OF JAMAICA. 15 



extensive, thorough, and painstaking studies of the fossil corals, includ- 

 ing: not only careful examination of all the material in hand, hut also 

 personal visits to nearly all the European Museums where the collections 

 of previous workers are preserved. His determinations have been the 

 chief reliance in the interpretation of many obscure points. His studies 

 will be published elsewhere more in exienso. 



PART I. 

 Geography and Physiography. 



The island of Jamaica is situated between ^N'orth Latitude 17° 40' and 

 18° 3' and West Longitude 75° 10' and 78° 23'. Its northern shore lies 

 almost due south of the western half of the Sierra Maestra coast line of 

 Cuba, from which it is 65 miles (nautical) distant. Between these 

 islands lies the eastward prolongation of the great Bartlett depression, 

 3,000 fathoms deep. The eastern coast is about the same distance from 

 Cape Tiburon, the western point of the island of Haiti, and is separated 

 therefrom by 1,000 fathoms of water. On the south lies a wide stretch 

 of the Caribbean, 2,000 fathoms deep. Cape Gracias a Dios, the nearest 

 Central American land on the western coast of Honduras, is 780 nautical 

 miles distant. Between the Isthmian-Honduran continental littoral and 

 Jamaica extends the Rosalind and Pedro Banks, less than 500 fathoms 

 deep, which constitute an extensive shallow submarine platform, indented 

 at one place by a narrow submarine strait of less than 1,000 fathoms. 



Jamaica is almost the exact centre of the great American Mediter- 

 ranean. By drawing straight lines through the island, as shown in 

 Figure 5, from Galveston to the mouth of the Orinoco, from the southern 

 point of Florida to the northern part of South America, from the eastern 

 end of the Antilles (St. Thomas) to the western indentations of the 

 Gulf of Honduras, and from the most northern Bahama to the Gulf of 

 Atrato, the central position of the island will be apparent, for it will be 

 found at the point of intersection of these radiating lines and about equi- 

 distant from their termini. This central position of the island is im- 

 portant from geographic, biologic, and geologic points of view, and makes 

 it a typical base of study for one interested in Antillean problems. 

 Like a measuring gauge set up in the middle of a stream to record the 

 rise and fall of a river, it stands in the centre of the American Mediter- 

 ranean, — a standard geological index of the great oscillatory changes 

 of level which have taken place in the history of Tropical America, whose 



