FORAMINIFERA FROM THE DEEP WELLS OF FLORIDA 

 (WITH MAP AND THREE PLATES IN TEXT) ' 



JOSEPH A. CUSHMAN 



A year ago I published the results of a preliminary study of the 

 foraminifera of a number of deep wells of Florida.* A general ac- 

 count of the geological formations encountered in the drilling was 

 given and but little attention was paid to the distribution of the 

 species themselves. This paper gives the systematic information 

 as to the foraminifera and especially those species of the Miocene 

 and Upper Eocene formations. Those of lower age are not specif- 

 ically described here as it is a rule of paleontology that new species 

 should not be described from well borings because of the uncer- 

 tainty of depth and the impossibility of giving a type locality from 

 which future collections may be made. As a result these are 

 simply placed in their genera and figures in most cases given in 

 order that they may be available for future comparisons. In the 

 previous paper already referred to mention was made of the sources 

 of error which should be kept in mind in the study of well borings. 

 Two things especially may again be noted : first that fossils may 

 fall down from levels above that at which the drilling is actually 

 taking place, especially when the well is not cased ; and secondly, 

 that fossils cannot be encountered until the depth has been reached 

 at which they occur. Therefore fossils appearing below a hori- 

 zon which has already been definitely fixed must have come from 

 above and are accidental at that level. Many of the foraminifera 

 from the well borings are not well preserved and little can be 

 made out except the genus to which they belong. Also in several 

 genera the different species have not been closely studied by work- 

 ers on the foraminifera. Among numerous genera such as Poly- 

 stomclla, Nonionina, Amphistegina, etc., there are many different 

 forms which are apparent in a study of the fossil material of 

 the Coastal Plain and West Indian areas. These are usually 



*Twelfth Annual Report of the Florida State Geological Survey, 1919, 

 PP- 77-103. 



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