those things are found almost always with clam shells from the ocean side.  some nice live ordnance.  they also come up in dredges during beach replenishment.  

I saw a beautiful mammath tooth taken by a scalloper off Chincoteague (pronounced shink-o-teeg) - about 60 miles out, he said - and there are lots of reports of aboriginal artifacts.  

bayside with the oysters, lots of abo and historic materials including the oldest date-bearing ceramic known from north america.  1580's or something like that.

A delmarva resident