114 STEPHEN TABER 



Fault phenomena of the type exhibited in the Antilles testify 

 to a state of tension rather than compression in the earth's 

 crust. This tension is difficult to explain. It may be due to 

 warping, for there is some evidence that the formation of the 

 troughs has been accompanied and perhaps, in part, preceded 

 by an upswelling or arching of the region together with more 

 or less subsidence of the border portions. The uplift has 

 culminated in the Island of Haiti, and the Bartlett Trough 

 has developed along the axis of uplift, the surface being in most 

 places higher near the borders of the trench than farther back. 

 Sea-terraces, marking intermittent elevations have been observed 

 along many coasts of the Antilles; in Cuba they extend entirely 

 around the east end of the island but attain their finest develop- 

 ment along the south coast between Cape Maisi and Guatanamo.^ 

 On the opposite side of the trough near Montego Bay, Jamaica, 

 they are also well developed, Hill having observed six distinct 

 benches.^ 



While the evidence is extremely meager it is at least in accord 

 with what is known concerning the structural relations of fault 

 troughs in the other parts of the earth. Most of these troughs ap- 

 pear to have been formed as a result of the upswelling of broad arches 

 and plateaus of the downwarping of basin-like areas under the in- 

 fluence of forces that probably have acted vertically. 



' R. T. Hill, Cuba and Porto Rico with the Other Islands of the West Indids, p. 44, 

 New York, 1899. 



= R. T. Hill, "The Geology and Physiography of Jamaica: Study of a Type of 

 AntiUean Development," Bull. Mus. Comp. Zool. Harvard College, XXXIV, GeoL 

 Ser. 4 (1899), p. 31. 



