I 



hill: geology of JAMAICA. 101 



The Falmouth Formation. 



On the coast of Trelawney, Hanover, and Westmoreland, immediately 

 adjacent to the sea and seldom rising more than 15 feet above it, there 

 is a formation of white chalky marl, usually friable but frequently in- 

 durated. In this are preserved numerous moUusks and fragments of 

 reef buildins: corals. The fossils retain all the nacre and other charac- 

 teristics of living species, and have been pronounced by Dall to be of 

 Post-Pliocene age. This formation indurates in places into a close 

 textured chalky white limestone, superficially indistinguishable from 

 many beds of the Oceanic Series, but on close examination it can always 

 be distinguished by the numerous fossils, as well as by its entirely 

 different microscopic structure, which shows it to be old beach marl. 

 Among the numerous fossils are many species still living in the adjacent 

 waters, including Strombidie and a small Bulla, the latter being the 

 same which is common in the limestone of Yucatan, the island of 

 Barbuda, and other localities in the West Indies. This formation i8 

 important, because it has wide occurrence throughout Tropical America, 

 and, when properly studied, will assist in general correlation. 



An outcrop of white limestone, similar to the Falmouth formation, 

 occurs at Hospital Point, north of Montego Bay. This contains the 

 remains of large Strombidse, and other well known species living in 

 the present sea. Fragments of coral heads of the reef building species 

 are quite common in this material. Good collections of the fossils of 

 the Falmouth formation were also made near Landovary about seven 

 miles west of St. Ann. These consisted of many molluscan species 

 associated with single heads of* reef coral. The formation here is so 

 indurated that it might well be termed white limestone, and easily 

 confused with the white limestones of the Oceanic Series. In St. 

 George and Metcalfe the formation consists of almost horizontal beds of 

 white marl with the mangrove oyster, between Canewood and Spanish 

 River, and from Low Layton to Retreat and Savanna Point. 



The Falmouth formation was nowhere seen to be more than half a 

 mile wide on the north coast, but on the southern coast of Westmore- 

 land, back of Savanna-la-Mar, it indents the country for a considerable 

 distance. Its occurrence at this locality has been well described by 

 Brown under the name of "White Marl " ^ and "Bulla Limestone."^ 

 Here it consists chiefly of a soft white lime marl, usually bedded, and 

 having some layers more eroded than others. Back from the coast the 



1 Jamaican Reports, pp. 229, 230. « Ibid., pp. 228, 229. 



