6 MICROSCOPICAL OBSERVATIONS. 



It is not merely the superficial layers which contain these remains, but earth 

 thrown out from the depth of fifteen to twenty feet, as at the excavations for 

 foundations and ditches at Fort Pulaski and Fort Johnson, abound in the same 

 fossils, among which, besides Spongiolites and Phytolitharia, the following Dia- 

 tomacese were noticed : 



Actinocyclus, several species. Pinnnlaria placentula, Kg. 

 Actinoptychus senarius, Ehr. elliptica, Kg. 



denarius. Ehr. Rhaphoneis rhombus, Ehr. 



Coscinodiscus radlatus, Ehr. Surirella splendida, Ehr. 



subtilis, Ehr. Triceratium favus, Ehr. 

 Cocconema cymbiforme, Ehr. alternans, B. 



*Eupodiscus radiatus, B. Terpsinoe musica, Ehr. 



GallioneDa sulcata, Ehr. Zygoceros rhombus, Ehr. 

 varians, Ehr. 



It will be noticed that all these forms are such as are now common in estu- 

 aries along the Atlantic coast. 



In a fresh water ditch, about a mile below the city of Savannah, and commu- 

 nicating directly with the river, I found the following Diatomacese in a living 

 state. 



Bacillaria paradoxa, Ehr. Pinnularia viridis, Ehr. 



Coscinodiscus subtilis, Ehr. *0dontella Mobilensis, B., with spicules of sponge 



Meloseira arenaria, Moore. 



In another fresh water ditch, in the same vicinity, I noticed among Drapar- 

 naldia glomerata, Ag., and Spirogyra quinina, Kg., the following forms, viz : 



Closterium lunuln, Ehr. Naunema, undetermined, with long slender 



frustules. 



Coscinodiscus excentricus, Ehr., dead Synedra vitrea. Ehr. 



Navicula hippocampus, Ehr. Surirella splendida, Ehr. 



SWAMP ON THE ROAD TO BONAVENTURE, NEAR SAVANNAH. 



On the 24th of December, I collected Hydrocharis spongiosa, or "Coltsfoot," 

 from a small swamp near the roadside, about a mile from Savannah ; and on 

 examining it with a microscope, I found that the small hairs which cover its 

 aquatic roots give an admirable display of the phenomena of the circulation of 

 the sap. These hairs are as transparent as glass, and in each one a turbid fluid 

 may be seen in rapid motion, along the walls of the cells. Slowly revolving 

 c t oblasts were also noticed in some of the hairs. Entangled among the roots 

 of this plant I noticed specimens of Hydatina senta, Ehr., and frustules of 

 Eunotia diodon, Elir. 



