AGASSIZ : THE FLORIDA ELEVATED EEEF. 41 



indistinct location of secondary sounds and sinks as may be indicated by 

 tbe many spurs and tongues, and islets and shoals, or long irregularly 

 shaped finger-like tongues of land, which abound in Barnes Sound, and 

 to the east all over the flats of the Bay of Florida. In many cases the 

 former connection of the keys with the mainland is only to be traced 

 from the innumerable small isolated islands scattered over the Bay of 

 Florida, in a line from Long Key to Cape Sable. In the part of the Bay 

 of Florida to the westward of that line, as far as Pine Keys, the man- 

 grove keys and islets, the remnants of the former easterly extension 

 of the mainland, have disappeared, while the group of keys to the west- 

 ward of a line passing through Bahia Honda (Plate XV.) attests the 

 former eastern extension of the peninsula of Florida, which has disap- 

 peared through the same process now seen so actively at work in the 

 district to the north of the outer line of keys from Long Key to Key 

 Biscayne. 



Sounds similar to those so prominent on the northeastern extremity 

 of the chain of Florida Keys — viz. Barnes, Card's Sound, and Key Bis- 

 cayne Bay (Plate XII.) — are repeated on a smaller scale from the Pine 

 Keys to Key West as far as the Marquesas. An examination of the 

 charts (Plate XV.) will show on many of the Pine Keys, Saddle Bunch 

 Keys, Boca Chica, and Key West the mode of formation of smaller 

 sounds ; the disintegration of the larger islands leaving sometimes 

 diminutive islands, or only narrow insular strips or angular spits and 

 projections as remnants of the islands formerly limiting the sounds. 

 These small and irregular sounds all discharge by so called creeks, 

 Pelot's Creek, Sugarloaf Creek, and other outlets, which allow the piled 

 up waters to escape and carry out the products of their disintegration 

 of the island due both to solution and to mechanical action. 



With the exception of Pine Keys, the surface of the keys from the 

 Marquesas to Key Largo is but indifferently wooded (Plates II., III.), 

 the vegetation consisting principally of a luxuriant fringe of mangroves 

 (Plate IX.) and of low bushes, with occasionally a tree of larger size. 

 On Key Largo and to the northward the trees are of larger size 

 (Plate IV.). 



Perhaps the most instructive part of the Florida Keys regarding the 

 formation of sounds is that part of Key Largo (Plate XII., and Coast 

 Survey Chart, Xo. 167) where we find the spurs indicating its former 

 connection with the mainland, forming on the one side Barnes Sound 

 and separating it from Card's Sound, and on the other Blackwater 

 Sound, flanked on the east by Barnes Sound, on the north by three 



