Donna,
The woman has a very lovely face. She is wearing a hat that appears to be what I would call a "toque" style which is trimmed with an ostrich plume and with French silk dotted veiling. I really cannot see the actual shape of the hat as the plume covers most it in the photo, so I cannot give the style a more exact name. It is also difficult to date the hat exactly as I really cannot see the details. However it looks like hats from the period of 1912 to 1915.