54 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
small bulrushes, lilies, and other water plants; the ponds are of most 
irregular and confusing shapes, so that it is a matter of much difficulty 
to travel twice over the same route; ponds may have wide connections, 
narrow connecting channels almost entirely hidden by saw-grass, or may 
be shut in by saw-grass completely. Oftentimes a tall man is unable to 
see a pond close at hand, so thick and high is the saw-grass. Scattered 
about in this sea of grass are islands of bushes and trees, called Keys. 
These keys seem to owe their origin to an accumulation of vegetable 
matter which may appear some inches above water level, during the dry 
season becoming partially dry (Plate XXIII. Fig. 2). During a night’s 
sleep upon them one’s bed is liable to settle to water level, and it is a 
common experience to break through to the knee in walking over them 
without feeling a firm foundation ; it is probable that the mat of grass 
roots or peat is what stops one’s downward progress. 
Origin of the Oolite. — The low undulations of the land surface in the 
pine belt can scarcely be accepted as evidence of former dunes. They 
would well accord, however, with the inequalities of a sea floor like the 
present one between the keys and the mainland. The cross-bedding 
and odlitic structure favor neither water nor wind as the primary agent 
in the construction of the rock. Therefore, since the land appears to be 
very young, being almost without soil and surface drainage ways, the 
topography favors an origin for the limestone in water, Elevation was 
apparently accompanied by slight folding, thus giving opportunity for 
the pine belt to develop and favoring the formation of a line of keys, in 
shallower water in the Everglades, approximately parallel with the edge 
of the pines and distant a few miles. This line of keys in the Ever- 
glades diverges southwestward from the pine belt just as the pine belt 
does from the elevated reefs.! 
1 It seems to me that Mr. Griswold is mistaken in ascribing an aqueous origin 
to the oólitic limestone he collected from the Everglades. From what I saw my- 
self of this limestone along the shore of Key Biscayne Bay, the rocks, which are 
the same as those collected from the inland by Mr. Griswold, consisted entirely 
either of patches of honeycombed wolian rock or of weathered elevated reef coral 
limestones, the жоПап rock having been blown into sinks, as 1 observed it at 
Boca Chica, so as to fill them, and as dunes rising to eighteen or even twenty feet 
on higher parts of the mainland. The decomposition and disintegration of the 
Everglades seems to me to indieate merely a later stage of disintegration, and one 
similar in every way to that going on between the keys and the present shore of 
the Florida mainland, a disintegration and decomposition affecting rocks of the 
same age and of the same constitution, — viz. ғоПап and elevated coral reef rocks, 
— and going on along the edges of the greater or smaller sinks, filled with aeolian 
sands, which separate the different parts of the elevated coral reef. Some of the 
