Yesturday after work I deceided to hit up a spot where I has stumbled across a piece of an pyritized ammonite.  This spot was in dallas county(upper cretaceous).  After all the rain we have been having I figured there had to be something.  When I got there the sun was already dropping and I have to look fast, I started off finding a few beat up pieces, and my luck changed, I saw what looked like a coin, but it was a perfect small ammonite, just larger than a penny.  The structure lines are great and it has a great metalic shine to it.  I was shocked to find it there.  I turned around to walk back through where I had already been and theres another, this one was 3 times the size, the only difference was that this one had pyrite caked on it.  Still in perfect shape as the other.  I walked a little farther before it became too dark and came across an oyster shell sticking out of the layer, the shell also had the pyrite all over it and had the mother of pearl shell still attached.  Just above the oyster shell was a piece of an ammonite also still in the layer, As I chipped it out, the bright white color started to show.  This piece was only about half of a whole ammonite, but had the brightest shell of anything I have ever found.  When the light hits it just right it just shines.