450 Notes on Natural Objects 



waves of the Bahama Channel break continually with great 

 violence. At the distance of three leagues, we have often 

 listened, morning and evening, to their roar, resembling remote 

 thunder. The Baxo enjoys a certain degree of celebrity here 

 for the abundance of fish, particularly of fine lobsters, in- 

 habiting its waters. Partly, therefore, for the sake of parti- 

 cipating in the amusement of fishing, and partly to study the 

 wonderful display of Nature's works in the structure of a coral 



reef, I joined my friend in his occasional excursions 



hither. » t \ i^oRimlo 



Our first visit was made by land ; and, after passing three 

 leagues through dense woods, perfumed with the blossoms of 

 oranges, limes, myrtles, and numerous other flowering trees, 

 we pitched our tent on the shore, among the wild figs and 

 sea grapes [Coccoloba sp.J. 



Near the coast, and bordering it for a few miles, is a belt 

 of honeycombed rock, evidently an ancient reef, attaining a 

 height of 20 ft. or 30 ft. above the present high water of the 

 sea. For a considerable space, this old reef forms a low pre- 

 cipitous cliff, against which the sea breaks ; but in other parts 

 of its course it recedes from the shore, leaving a breadth of 

 half a mile or more of woody ground and sand-hills, covered 

 with the sea grape, between it and the present coast line. 

 This rock is externally hard and honeycombed, its surface 

 being covered with sharp points and protuberances. In ge- 

 neral, it consists of an aggregation of broken corals and 

 madrepores of great size. Amongst them are numerous 

 spines of .Echini, and univalve and bivalve shells, the internal 

 parts of which are filled with indurated coral sand, furnishing 

 a good example of the progress towards consolidation of a 

 shelly limestone resembling many older rocks, the oolites for 

 instance. From hence I collected a series of specimens il- 

 lustrative of this solidifying process, or the complete incor- 

 poration of the shelly portion with the surrounding calcareous 

 rock, by the filling up of their cavities, and by the cementing 

 together of the various organic and fragmentary substances* .-, 



Within this belt of comparatively recent rock, the country 

 inland consists of rocks of the serpentine class, diallage, 

 greenstone, and numerous modified rocks, attesting that great 

 alteration in their structure has taken place by igneous causes. 



In connexion with these reefs, which border the coast of 

 Cuba, are some circumstances which offer matter for specu- 

 lation. The old reef, which we have traced passing from the 

 shore to more than half a mile inland, has been stated to rise 

 to some 20 ft. or 30 ft. above the present high-water level. 

 Now, as the coral insects do not live above high water, and, 



