The delicate spiral helmet shell the Scotch Bonnet became the official North Carolina State Shell in 1965.  Dare County state representative Moncie Daniels of Manteo introduced the legislation in the North Carolina General Assembly.  It wasn't however an easy sell.  The Scotch Bonnet is easiest to find on the secluded beaches of Ocracoke Island and in inhabited Portsmouth Island south of Ocracoke where they are found in great numbers after a storm. 

While North Carolina was the first state to select a state shell, others followed. 
Rhode Island - Quahaug
Florida - Horse Conch. 
South Carolina - Lettered Olive
Virginia - Oyster