It is a partial fish jaw, probably Trichiurus sp. Hairtail fish. See: http://www.elasmo.com/frameMe.html?file=leecreek/lc_fish/lc_fishSpp.html&menu=bin/menu_leecreek-alt.html click on The teleosts on the top of the page. More specifically: http://www.elasmo.com/leecreek/lc_fish/fishSp.html?tgtSp=tric_sp