18'jr.] OVO [Cubhing. 



the physiograpliy of the Lower Gulf section of Florida which best 

 exemplifies them, will not be amiss. 



Tlie whole coast, even from as far north as Tarpon Springs to the 

 extreme end of the Peninsula, is low^ and sandy ; the highest natural 

 land rarely rising more than a few feet above high-tide level, and 

 the loftiest dunes nowhere reaching an altitude of over fifty feet. 

 Geologically, Florida, Prof. W J McGee tells me, is an extension of the 

 lowland zone — made up of later mezozoic and cenozoic deposits — fring- 

 ing our Atlantic and Gulf coasts, and, as one of your Secretaries, Dr. 

 Persifor Frazer, also states, reappearing in several of the Antillean 

 islands. Especially do the prevailing formations of Florida resemble 

 those of the Peninsula of Yucatan. They are of very pervioi;s limestone, 

 and from above the region of Charlotte Harbor southw^ardly, are inter- 

 spersed with phosphatic beds, also of organic origin. But whether indu- 

 rated, as are the lowermost, or less solid as are the more superficial, these 

 formations are, like the overljang soil, excessively sandy. Hence they 

 are not only pervious, but also, very soluble in the acids of fresh surface- 

 or rain-water. One of the consequences of this is, that areas of varying 

 extent and in lines generally parallel with the courses of the open rivers 

 and inlets of the country, and of their tributaries, are subject to under- 

 mining by these corrosive processes ; have fallen in, forming first deep 

 lakes, then, as these in time have become filled, morasses, in the central 

 lagoons of which, thi-ough the peculiar habits of alligators and other 

 aquatic creatures, circular mud-banks have been thrown up, becom- 

 ing cypress islets, and, finally, the foundations of hammocks, or 

 marsh-keys like those of the Anclote region — built there by man in 

 later ages. Everywhere, too, along the lines of narrower subterra- 

 nean rivers formed by more restricted dissolving aw^ay of the under- 

 lying formations, series of perfectly round, hopper-shaped sinks 

 occur, seemingly fathomless, containing pellucid or deep green water, 

 and reminding one measurably, not only of the round, artificial drainage 

 basins of the keys, but also of the more natural (and in some ways 

 identical) (jenotes or ancient well-caves of Yucatan and other portions of 

 Central America. 



Not to enter as fully as I ought into a discussion of the physiographj- 

 of this inner portion of the coast — so suited to settlement by a people 

 like the key dwellers, when they came inland — I may say that the con- 

 ditions described render the whole region peculiarly unstable. This 

 has been especially true of the actual coast. Everywhere it is indented 

 by such tidal inlets as the Manatee and Pease, or their sluggish inland 

 extensions called rivers, like those of Anclote, and those that put out 

 from the north and east of Charlotte Harbor, and those wiiich every- 

 where radiate sinuously in the same general directions, from the great 

 indentation or bay that contains the Ten Thousand Islands. In a land 

 so broken and low as this, the hurricane has wrought continuous change 

 of shore-line, and 'tis but natural, too, that its coast should be skirted 



PROC. AMEK PHII.OS. SOC. XXXV. 153. 2 X. PRINTED AUGUST 3, 1897. 



