Looking for help in identifying this insulator. I can't decide, so would appreciate any information. More photos to come.

I acquired this insulator this week on my travels in northern Alberta. (F-Skirt) H.G.CO.; (R-Skirt) PAT MAY 2 1893 (The lettering is very hard to read, and even harder to photograph. I have had several people look at it and there doesn't appear to be any dots on the rear skirt.); SDP

[id=129581662]