80 FLORIDA GEOLOGICAL SURVEY-NINTH ANNUAL REPORT. 
Donax tumida Phil. X 
Mulinia lateralis Say X 
Mulinia lateralis (long variety) 
Mulinia lateralis var. corbuloides Desh. X 
Mactra (yo.) 
Spisula solidissima var. senulis Say X 
Rangia cf. cyrenoides Desmoulins 
Corbula cuneata (?) Say ? 
CORALS 
Oculina robusta Pourtales X 
Solenastraea hyade (Dana) X 
BRYOZOA 
Cupularia denticulata Lamarck. 
5 By referring to the list it is seen that sixty-one species of mol- 
lusks are. recognized as identical with living forms. One species, 
Transennella caloosana Dali, has not been reported from deposits 
later than the Pleistocene. One other species, an Area, is regarded 
as intermediate, between the extinct A. limitla and the recent A. 
ponderosa. One specimen is referred doubtfully to Corbula cune¬ 
ata, a species not known in the recent fauna. The collection con¬ 
tains, in addition, several species, the identification of which is 
doubtful. Among these is a shell near to Pliacoides nasuta, which 
may possibly represent a new species. In this connection it may be 
noted that Shimek has presented evidence showing that the land and 
fresh-water molluscan fauna from as early in the Pleistocene as the 
Aftonian inter-glacial stage has remained essentially unchanged to 
the present day, while the vertebrate fauna of the same stage has 
become largely extinct.* Likewise at this locality in Florida a 
vertebrate fauna containing many extinct species is associated with 
a land and fresh-water molluscan fauna containing so far as known 
only recent species. This vertebrate fauna also is more recent than 
the marine molluscan fauna of the underlying beds which, with few 
exceptions, includes species identical with the living forms. It is 
evident, therefore, that the presence of existing species of mollusks 
in the formation cannot be taken as proof that the deposits are 
recent, especially in view of the presence of extinct species of verte¬ 
brates and plants. 
*Evidence that the Fossiliferous Gravel and Sand Beds of Iowa and Ne¬ 
braska are Aftonian, by B. Shimek. Bull. Geol. Soc. of Amer. Vol. 21, pp. 
119-140, 1910. 
