I've seen something similiar in the illustrations contained in ancient maps. I have a CD ROM of these maps at the office and will take a look tomorrow.
If anybody else is looking you might want to try
http://www.eyewire.com/products/illustration/circaart/ Just look at the PDFs of angels/ancient maps and so forth. (a lot of these images are snips from classical paintings).
Based on my knowledge of history (I'm no expert though) my best guestimate is it might be Art Nouveau or Art Deco in origin.
Hope this helps in the hunt.