32 bulletin: museum of comparative zoology. 



edge crops out on the north side of Bahia Honda. The elevated reef at 

 Bahia Honda is the most western point to which portions of the inner 

 elevated reef have been traced. Undoubtedly there are patches of it 

 still left in from two to three feet of water off the line of keys extend- 

 ing westward from Big Pine Key as far as Key West, and peidiaps off 

 the keys to the westward of that island. But west of Bahia Honda the 

 inner elevated reef has been eroded, and no part of it reaches the surface. 

 The material derived from this erosion having gone in great part as asolian 

 sand to build up the line of keys to the west of Bahia Honda. 



At Boot Key we found a patch of the elevated reef about two feet 

 above high-water mark, honeycombed, pitted, and full of heads of Mae- 

 andrina, Orbicella, and Colpophyllia, as well as of massive conchs. A 

 coral sand beach covers the elevated reef to the eastward, but it crops 

 out again farther east, as well as westward. In these patches occurred 

 the same species of corals. The borders of the elevated reef were covered 

 with masses of tests of Echini, of fragments of Gorgonians, of sponges, 

 and of blocks made up of bivalves which had become cemented to- 

 gether. This material, if overwhelmed with calcareous sand and ce- 

 mented and hardened, would form a magnificent bed of fossils. The 

 upper parts of the beaches flanking the patch of elevated reef are covered 

 with masses of Porites and of bivalves, and as we approach low-water 

 mark this material is ground to fine powder. 



The elevated reef at Indian Key (Plates VI., VII.) rises about six feet 

 above high-water mark. It is exposed along the greater part of the 

 outer edge of the island. Towards the interior the island is covered 

 with low vegetation, and the surface of the higher parts of the elevated 

 reef has been changed to a hard ringing limestone. The outer edge of 

 the reef is pitted and honeycombed, and full of small pot-holes ; the 

 sea is gradually encroaching upon the sea face of the reef, and eating 

 slowly into the island. The corals observed are mainly species of 

 Orbicella, Colpophyllia, and Mseandrina. 



At the eastern extremity of Lower Matecumbe the elevated reef, which 

 is hidden by coral sand for the greater length of the island, has been ex- 

 posed by the hurricane of September, 1894. During that hurricane 

 about sixty feet in width of the coral sand beach was carried away, 

 leaving the underlying elevated coral reef fully exposed, but not more 

 than twelve to fifteen inches above high-water mark, very much lower 

 than at Indian Key. 



We examined the shores of Key Largo at two points, one near the 

 in extremity of Card's Sound, the other about half-way between 



