MUSEUM OF COMPARATIVE ZOOLOGY. 147 
year. An inspection of the western face of the Miami Reef leaves in 
my mind no doubt that the process of solution is rapidly extending 
the general plane of the Everglades to the eastward. On the floor of 
the more level and lower lying country which constitutes the eastern 
margin of the Everglade district, we find a similar deposit of limy 
matter, which has been laid down during the process of evaporation 
of the swamp waters. At the distance of half a mile from the face of 
the Miami Reef, this layer was very much thinner than on the lower 
portions of the reef itself. In the Everglade district the amount of 
decaying vegetable matter is great, and there can be no doubt that 
running waters of this region become heavily charged with carbon di- 
oxide, and are thus enabled to dissolve the limy matter with which 
they come in contact. In the rainy season, as before remarked, these 
waters rise to the height of from five to eight feet above their level 
during the dry season, when I observed the district. As the waters of 
this swamp rise, they doubtless take a large quantity of the lime into 
solution. After the rainy season passes, the water is drained away by 
the numerous exits to the sea. 
It is a noteworthy fact that Biscayne Bay, which receives through the 
Miami and other streams discharging from the swamps of the Ever- 
glades on its floor a vast amount of limestone mud. A portion of this 
mud is composed of the remains of Foraminifera and other organisms ; 
but microscopic examination of it shows that a large portion of the mass 
does not exhibit evidence of having recently been in the organic con- 
dition. It appears to be lime in the form which would be given it by 
a precipitation from water. The quantity of this mud in the control 
of the tidal and other currents which sweep through these embayed 
waters is very remarkable. The volume of the material can best be 
judged by the conditions exhibited by the deposits of limy matter at 
the eastward end of the channel passing from Biscayne Bay to the sea, 
at the point known as Cesar’s Creek. The calcareous ooze moving out 
from the Bay of Biscayne at this point is so large in amount, that it 
forms a distinct delta, digitated at its seaward end in substantially the 
same manner as the mouth of the Mississippi. It seems clear that this 
great volume of mud comes from Biscayne Bay, and it would be difficult 
to explain its origin by any action originating altogether in that basin. 
I am disposed to believe that the surcharge of lime given to the sea by 
the effluent water of the rivers which drain the Everglades leads to the 
formation of a portion of this ooze by precipitation. 
However it may be as to the origin of the limestone ooze, so plenti- 
