204 CORALS AND CORAL ISLANDS. 



board, and was worn into a range of columns, or excavated 

 with caverns, so as to look very much broken, though quite 

 regularly even in the level of the top line. 



We might continue these descriptions ; but the above, 

 with the details before given, will convey a general idea of the 

 whole. 



Florida Reefs and Keys. — This region of coral formations 

 has been described by Prof. M. Tuomey {American Jour- 

 nal of Science, vol. xi., 1851), Professor Agassiz (Coast Sur- 

 vey Reports for 1851 and 1866, and Bull. Mus. Comp. Zool., 

 i., 363), and Captain E. B. Hunt (Am. J. Sci., xxxv., 1863). 

 A few paragraphs from the papers of the first two of these 

 observers are here cited. The map, at the close of the volume, 

 illustrating this Florida reef-region, is from the Report on 

 Deep-Sea Corals of L. F. de Pourtales, published in the Illus- 

 trated Catalogue of the Museum of Comparative Zoology in 

 1871. First, from Professor Tuomey: 



" Key West is about six miles in length and two miles wide, 

 the highest point being fifteen or twenty feet above mean tide. 

 The deepest wells are about fifteen feet in depth ; the water in 

 them, which is slightly brackish, ebbs and flows with the tide." 

 " The rock perforated in these wells, like that everywhere else 

 exposed, is sufficiently soft to yield readily to the axe, with 

 the exception of a thin crust of a few inches on the surface, 

 which is quite hard, especially where it is exposed alternately 

 to the action of the tides and atmosphere. This indurated 

 crust may be seen on the road between the town and the bar- 

 racks, and around the salt works. Below this crust the rock 

 is quite soft, and in some other respects resembles the Ala- 

 bama white limestone ; but the most striking difference next 

 to that of organic remains, consists in the distinctly oolitic 



