SALT KEY BANE. 215 



lar, the beds slanting toward the sea at an angle of about 

 seven degrees. Upon this foundation immense masses of 

 Strombus, dead shells, and corals have been thrown in banks, 

 evidently the beginning of deposits similar to those already 

 consolidated below ; but there is this difference in their forma- 

 tion, namely, that while the foundation rock is slightly inclined, 

 and never rises above the level of high water, the accumula- 

 tion of loose materials above water level forms steeper banks, 

 varying from fifteen to twenty and thirty degrees. In some 

 localities broken shells prevail ; in others, coarse and fine sand ; 

 and the ridges thus formed, evidently by the action of high 

 waves, rise to about twelve and fifteen feet. This is evidently 

 the foundation for the accumulation of finer sand driven by 

 the wind over these ridges, and forming high sand-dunes, 

 held together by a variety of plants, among which a trailing 

 vine {Batatas littoralis), various grasses, and shrubs are the 

 most conspicuous. These dunes rise to about twenty feet ; 

 on their lee side and almost to their summits grow a little 

 palmetto. The sand of the dunes is still loose, but here 

 and there shows a tendency to incrustation at the surface. 

 The slope of these dunes is rather steep, sometimes over thir- 

 ty degrees, and steeper to the seaward than on the landward 

 side. 



" In the interior of Salt Key there is a pool of intensely 

 salt water, the tint of which is pinkish or flesh -colored, owing 

 to the accumulation of a small alga. When agitated by the 

 wind, this pool is hedged all around by foam of the purest 

 white, arising from the frothing of the viscous water. Along 

 the edge the accumulation of this microscopic plant forms 

 large cakes, not unlike decaying meat, and of a very offensive 

 odor. The foundation rock of this Key is exactly like what 

 Gressly described as the ''fades coralMen'* of the Jurassic 



