AGASSIZ: BAHAMAS. 155 



393) is formed of remarkable limestone cliffs from one hundred and fifty 

 to two hundred feet high. The projecting parts of the island in the 

 vicinity of Aquin Bay consist of very remarkable bold white cliffs and 

 hills resembling chalk, which occur both on the south and on the north 

 coasts. There are coral reefs all along the shores of the island. The 

 100 fathom line adds but little to the extent of San Domingo, which is 

 separated from Porto Rico by a channel, the greatest depth of which is 

 only two hundred and sixty fathoms. The area of Jamaica would be 

 greatly extended on its southern face by the addition of the plateau 

 formed by the 100 fathom line. Extensive areas of elevated tertiary 

 limestones have been traced along the coasts of Jamaica and of San 

 Domingo. 



Between the eastern point of Haiti and Jamaica are the small island 

 of Navassa and the Formigas Bank. Xavassa (Hydrographic Chart Xo. 

 379, Admiralty Charts Xos. 461, 486) is about three hundred feet high. 

 It rises from a small bank of soundings one third to three quarters of 

 a mile broad. There is a patch of corals on the north end of the isl- 

 and. Formigas Bank (Hydrographic Chart No. 373, Admiralty Chart 

 Xo. 486) is eight miles in length ; the bottom is rocky, with a general 

 depth of from five to seven fathoms. There are narrow veins of sand 

 near the edge, in from nine to eighteen fathoms. 



To the southeast of Jamaica are the Morant Cays, a group of small 

 cays seven to ten feet high, forming with the adjacent reefs a crescent 

 bank convex to the southeast of about three by one and a half miles 

 wide. These cays rise from an elongated bank about twelve miles by 

 four within the 100 fathom line, with depths close to it ranging outside 

 of the reef from seven to eighteen fathoms, and thirty to fifty near the 

 edge of the bank. A terrace is said to rise seventy-five feet all round 

 the island, composed of ringing and honeycombed limestone. The Alba- 

 tross Bank lies to the northeast of the Morant Cays, and is a similar 

 bank ; it carries, however, from nineteen to thirty fathoms close to the 

 100 fathom line, and is marked on the charts as coral sand. 



Fringing and detached reefs abound on the south shores of Jamaica. 

 They are especially numerous from Morant Point to the west of Kings- 

 ton Harbor as far as Portland Point, although they extend, irregularly 

 distributed in favorable localities, to the western extremity of the island 

 off Alligator. Point, and from Pedro Bay to St. John's Point (Admiralty 

 Chart No. 255, Hydrographic Charts Nos. 347, 373). 



