18 FLORIDA REEFS. 



in width. Nowhere does it rise more than thirteen feet above the level of 

 the sea. The hill ninety feet high, said to exist on its eastern extremity, 

 resolves itself into a tuft of very high mangroves. 



The vegetation of the whole key is very rich, the trees more diversified 

 and larger than on any other island in the range. The rock formations are 

 also very diversified. The seaward shore is rather abrupt, the ocean hav- 

 ing worn away the sloping edges. The foundation of the key consists 

 chiefly of large coral boulders, the flat Ma3andrina heads being most numer- 

 ous, though Porites and Astra3ans are also abundant. They are so dis- 

 tributed upon the lower level of the island that one would think they had 

 grown where they are found. On closer examination they are seen to be 

 detached coral heads heaped together, and, owing to their peculiar form, 

 stranded in an upright position. Whoever has seen Ma^andriua heads broken 

 off by boring shells will not wonder to see these flat hemispheres resting on 

 their broad, flat bases rather than on their rounded side. But though they 

 are thus found in their natural position, suggesting the idea that they have 

 grown where they now lie, the fact that among them are some which are 

 overturned, and others broken in halves, contradicts this conclusion, and 

 show that, notwithstanding the regularity of the foundation, this key, like 

 the others, rests on an accumulation of detached coral boulders. Indian 

 Key has a similar foundation ; the evenness of the accumulation and the 

 natural position of the heads misled me at first into the belief that I had 

 found a proof of the upheaval of the keys. But a closer survey satisfied me 

 that their upper formations consist here, as elsewhere, of coarse and fine 

 oolites, with intervening seams, as at Key West, of compact Ihnestone, and 

 an overlying crust whereon the sea does not encroach upon the older 

 formations. 



As has already been remarked, the shore is rocky, and, except in small 

 patches, no sand beach is seen along this extensive island. There are, how- 

 ever, large mud flats along its southeastern extremity, among which rise 

 Key Rodriguez, Dove Island, two Mangrove Keys, and another off Plantation 

 Island, known as Tavernier Key. These mud flats abound in animals of all 

 kinds. Nowhere are Holothuria more numerous ; cartloads might easily be 

 gathered. The Eunices are also more numerous than elsewhere, and 

 nothing can exceed the beauty of the Actinias, Gorgonias, and Chitons to be 

 found on every rock upon the shore. The best evidence that Key Largo, 

 notwithstanding the fictitious height assigned to some parts of it, may 



