I looked it up in my Peterson's guide, looks like a White Sheep or possibly Pronghorn according to their skull guide. They both live in NW Canada.
I think what HD said holds a lot of promise too! <img src="/ubbthreads/images/graemlins/grin.gif" alt="" /> <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />