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Roger Weller, geology instructor

by Elizabeth Wolfe
Physical Geology
Fall 2010

Problem Fossils
  (Fish Ballasts)


          Are they brains?  Are they ribs?  Are they fish helmets?  Well the mystery has been solved! 

         These small fossils that resemble brains are actually fish ballast.  These fossils are on average about one inch with bilateral symmetry and are quite dense.

         You may be wondering just what are fish ballast.  Well they are the enlarged spines of fish.[1]  Some fish, like sea cows, have enlarged bones to help weigh them down while in the water.[2]

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[1] Fish fossils found in Florida.  Retrieved November 9, 2010 from 

[2] Mayell, Hillary (October 10, 2001).  Legged sea cow fossil found in Jamaica.  Retrieved November 9, 2010 from National Geographic.