28 IN LOWER FLORIDA WILDS 



siding of this region certainly aids the sea very 

 materially in the destruction of the land. There 

 is no reason to doubt that the bays along the south 

 and southeast mainland coasts are slowly deepen- 

 ing and encroaching upon the land. 



The sea water cannot dissolve all the limestone 

 which it destroys but it leaves a small residue. 

 This residue serves to augment the mud flats of 

 the bays and tidal channels. This is well seen 

 at the mouth of Caesar's Creek and in the several 

 passages between Largo and Elliott's keys. In his 

 Observations upon the Floridas, published in 1823, 

 Charles Vignoles stated that Key Largo was a 

 peninsula, connected with the mainland by a 

 portage of six boat-lengths, though now a navi- 

 gable channel separates the two. A cotton rat 

 (Sigmodon hispidus) and a cotton mouse (Pero- 

 myscus gossipium) both dry -land and swamp -fre- 

 quenting animals, but not swimmers, are found 

 on Key Largo, which would indicate that there 

 was formerly a land connection between the 

 mainland and the island. It is quite probable 

 that the water passage separating the two bodies of 

 land may be due to both solution and subsidence. 

 The former connecting neck of land did not, how- 



