Stormwater ditch

[hemi123]

So noticed a few weeks ago that the stormwater division was widening and refortifying a drainage ditch in N. Charleston SC. So as you all suggest and I always try to do I got permission to search the area and came up with many Great White and Angustiden teeth as well as many many bones I could not identify. However this thick, what I assume is a rib bone caught my attention being so thick. The ditch is in the Miocene/Pliocene era Im assuming and just wondering if this would be a whale rib or a dugong. Any suggestions would be great. 

[hemi123]

Here is another shot for width.

[Fossildude19]

I would think dugong.   

 

[sixgill pete]

Great whites and angustidens? Sounds like you may have Pliocene/Pleistocene layer overlaying an Oligocene layer. Which would be possible in the Charleston area. As far as your "bone", I am not so sure it is dugong.  Could we see good in focus pics of both ends. With it being the central focus of the picture. Taken as close up as possible.