GLIMPSES OF LIFE ALONG A CORAL REEF. 317 



distance by their slight diflFerences in contour. The position of our 

 key, which we had left behind, was shown by the top of its tall co- 

 coanut palms long after the island itself had dipped below the water. 

 Taking a northwest course up the channel, Abaco is seen as a low bar- 

 rier on our left, while at a greater distance it looks like an undulating 

 green ribbon between the sky and sea. We pass numerous small keys 



Fig. 2.— Gbeen Turtle Key, bearing three miles Northeast. (From a sketch made from 



the deck of a schooner.) 



and rocks on the right, between which long white lines of breakers 

 may be seen, marking the outer reef. "VVe are frequently near enough 

 to the " mainland " to see its dense forests of pine, its palms fringing 

 the shore, the narrow beaches of white coral-sand, with here and 

 there a thatched hut fronting a pineapple field, which may be dis- 

 tinguished by the small clearings in the woods. 



The keys present the greatest variety in size and form, from a 

 bare rock no larger than a buoy to islands five or six miles long. The 

 latter are very narrow, and are usually covered with a thick growth 

 of shrubs and small trees w^hich, excepting a few palms, rarely exceed 

 fifteen or twenty feet in height. The islands are scattered along 

 closely together, or occasionally separated by wide channels. The 

 soil has to be very thin indeed, which can not support a variety of 

 shrubs, which seem to grow out of the very rocks and to live upon 

 the air. Some of the smaller keys are mantled with vines and climb- 

 ing plants, such as smilax, convolvuli, and rock samphire, with here 

 and there some low shrubbery at the water's edge. 



The coral-rock which forms the basis of the islands crops out at 

 many points, and is always exposed around the shores where these are 

 not covered by a sand-beach. Freshly-broken surfaces have a light- 

 cream color, but weather to a uniform grayish tint. This limestone is 

 so soft that it can be readily sawn or chopped with an axe. Conse- 

 quently, the waves denude it rapidly, forming the white coral-sand, 

 which is distributed as a fine deposit over the sea-bottom and as 

 stretches of smooth beach. The shores overarch where they are at all 

 precipitous, roofing a wide cavern below, in which the ceaseless roar 

 of the waves may be heard at a long distance. Where a single rock 



