than 150 ft. These environments may be recognized and differentiated by noting the 
relative abundance of individuals belonging to the various families without regard to the 
species or genera involved. 
1953 - 1954 
Ginsburg, R. N., L. B. Isham, S. J. Bein, and J. Kuperberg (1954) Laminated algal sediments 
of South Florida and their recognition in the fossil record. Final Rep. 54-20 to the National 
Science Foundation from the Marine Laboratory, University of Miami., Coral Gables, FL. 33 
pp. + Figs. 
(DATE OF SAMPLING UNKNOWN OR NOT APPLICABLE.] Laminated structures in 
calcareous rocks (stromatolites) which are abundant in the Pre-Cambrian and Paleozoic 
have been interpreted as algal from their gross morphologic similarities with modern 
forms. In order to develop more rigorous criteria of algal origin, to determine what 
class of algae were responsible for these structures, and to assess their environmental 
significance, laminated sediments forming in South Florida intertidal zones were 
studied. The sediments consist of alternately dark and light colored laminae of the order 
of a millimeter in thickness. The light laminae are fine-grained detrital sediment, and 
the darker ones contain varying amounts of algal debris. Definitely recognizable calcium 
carbonate precipitated as a result of algal photosynthesis is not quantitatively 
important in these deposits. A variety of structures such as domes, bubbles, 
undulations, and unconformities, all on several scales, are produced by differential 
sedimentation, preferential algal growth and sediment binding, configuration of the 
substrate, and desiccation. The laminations are formed by the alternation of heavy 
sedimentation with the growth of a mat of blue-green algae and associated organisms. 
Two end member types of organic mats and sediments are described, one from the 
rocky platforms of the open intertidal zone, and one from the intermittently flooded 
mud flats. The distinction between the two is based on the relative and absolute 
thickness of the mats and sediment laminae, structures, and grain size. Reference 
horizons of quartz grains which were established at several localities showed that the 
laminae are not necessarily annual and that their time value is variable and also 
depends on environments Criteria for the recognition of ancient stromatolites as 
deposits of this type are based on the presence of detrital sediment, and of structures 
which required a sediment-binding surface film. Because these recent algal-laminated 
sediments are limited to within a few feet of mean sea level, stromatolites of this type 
are perhaps the most reliable organic indicator of sea level available. Furthermore, 
because of the relationship between the properties and structures of the sediments and 
environment, they may provide useful geographic information. Study sites included 
Manatee Basin, Crane Key, and rocky platforms in the lower Florida Keys. 
1953 - 1958 
Turney, W. J., and B. F. Perkins (1972) Molluscan distribution in Florida Bay. Sedimenta III . 
R. N. Ginsburg (ed.) Univ. of Miami Rosenstiel School of Marine and Atmospheric Science, 
Miami, FL. 37 pp. 
[THIS STUDY FIRST APPEARED IN SHELL OIL COMPANY REPORTS IN 1958 AND WAS 
REVISED FOR PUBLICATION IN THIS WORK. SAMPLING DATES WERE REPORTED IN 
SCHMIDT (1991) AS 1953 - 1958.] Within Florida Bay, four subenvironments can be 
recognized by the physical characteristics of salinity and variability of salinity, water 
circulation, and wind. The Northern Subenvironment is characterized by low and 
variable salinities due to freshwater runoff from the Florida mainland. The Interior 
Subenvironment is characterized by restricted circulation and is relatively unaffected 
by tidal exchange with either the Gulf of Mexico or the Atlantic Ocean. It is subject to 
large salinity variations due to seasonal or annual climatic variations. The Atlantic 
Subenvironment has near-normal marine salinity, with mixing of waters with the 
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