Why is my Cameo Carving different

by Loo
(Australia)

Hi there folks, very very new to this cameo game.. I'd be flat out telling you how long its been in the family, let alone its age... Anyway, my question is, why is the head of my cameo carved across the narrowest part of the item, where every other cameo i have seen, the head runs up and down the longest parts of the piece. Can someone date and authenticate this cameo for me...