92 STEPHEN TABER 



THE BARTLETT TROUGH^ 



The Bartlett Trough is probably the most striking physiographic 

 feature of the Antillean region (Fig. i). It is a long, narrow trench 

 stretching from the Gulf of Honduras eastward into Gonaive 

 Gulf between the two western peninsulas of Haiti, a distance of 

 15° or 1,570 km. Its width, where widest, between Cuba and 

 Jamaica and near the Cayman Islands is 150 to 160 km. Its 

 deepest sounding, 3,506 fathoms (6,412 m.) was obtained less than 

 50 km. from the coast of Cuba and is over 8,275 m. below the 

 higher peaks of the Blue Mountains in Jamaica and the Sierra 

 Maestra in southern Cuba. The six deepest places (all over 3,000 

 fathoms) are close to the inclosing scarps rather than near the center 

 of the trough. The floor of the trough seems to be relatively flat 

 over quite large areas, but in longitudinal profile rises and falls 

 throughout its length. The Bartlett Trough lies between two 

 great fault zones which may be traced longitudinally far beyond 

 the limits of the trough itself. They are here designated the Swan 

 Island-Jamaica-South Haiti fault zone and the Cayman Islands- 

 Sierra Maestra-North Haiti fault zone. 



Swan Island- Jamaica-South Haiti Fault Zone. — This fault 

 zone may be traced westward from its juncture with the 

 northern escarpment of the Caribbean Basin in the vicinity of 

 Ocoa Bay, Santo Domingo, across Haiti, and along the southern 

 side of the great Bartlett Trough. On the Island of Haiti it is 

 marked by a trough-shaped valley 15 to 20 km. in width, which 

 extends from Barahona on Neyba Bay to Port-au-Prince, a dis- 

 tance of about 150 km. Throughout its length this depression 

 is confined between the precipitous fronts of two lofty mountain 

 ranges. The floor of the trough comprises the plain of the Cul de 

 Sac in the west, the plains of Neyba in the east, and the lake region 

 lying between. Two of the lakes contain salt water, and 

 W. F. Jones states that they are both below sea-level, but at differ- 

 ent elevations.^ A very sHght subsidence of the land would com- 



' A brief description of this trough was given in a previous paper, "Jamaica 

 Earthquakes and the Bartlett Trough," Bull. Seis. Soc. of Amer., Vol. X (1920), 

 pp. 84-88. 



*W. F. Jones, "A Geological Reconnaissance in Haiti, A Contribution to 

 Antillean Geology," Jour. Geol., Vol. XXVI (1918), p. 730. 



