This paper is devoted to the recording & description of the molluscan fossils contained in the Fargo & Locklin collection from N. St. Petersburg, FL, & now in the collections of the Acad. of Natural Sciences of Phila. This locality holds a special interest in the geology of Florida since it represents the most northwesterly known exposures of the widespread Caloosahatchee formation of southern Florida, made famous through the monumental work of William Dall on the tertiary Paleontology of Florida. It is also noteworthy because of the general fine state of preservation of its fossil remains. Numerous species from other localities of the Caloosahatchee, as well as some Recent & Miocene species, have been described & figured. 50 black & white plates.