American Lady circa 1800

This lovely lady has arrived in fine condition.  She measures 25 x 30.  Her head is so high in the painting I wonder if the canvas wasn't cut down sometime and might have been more of a 40 x 50 originally.   She was in the catalog as American, ca. 1800.   I suspect she is wearing a fashionable wig. 

The frame appeared to be newer but when I saw the back I could tell it had some age also.   As usual, there are no identifying marks and no name of the sitter or the artist.