The Wm A Rogers name is quite common in silver mostly because so many companies used his name. The most recognizable being Oneida from 1929-1978. There is a brief detailing here for the history:
http://wiki.answers.com/Q/Who_is_Wm_A_Rogers_who_was_associated_with_Oneida I haven't run across "Canada" but after googling, I see some pieces are marked with Canada. Makes me suspect that it was issued under Oneida since they have a Canadian operation.
You could start with replacements.com. I may be able to search a little later today.
The 150 would be the "pattern number". This is probably not the right name but think of it as that
It identifies the the pattern and sometimes you can guesstimate a date by this number.
I am wondering if this little guy had a lid at one time... I'm with Mario. If it's not a salt, it would make a nice one.