I picked up this novel, "High Towers" by Thomas B. Costain, because the cover caught my eye.  It didn’t hurt that it only cost (inexplicably) 26 cents.

https://mail.google.com/mail/?ui=2&ik=21175d1a78&view=att&th=13041bdc5a1779d7&attid=0.1&disp=emb&zw

https://mail.google.com/mail/?ui=2&ik=21175d1a78&view=att&th=13041be2acbabf3f&attid=0.1&disp=emb&zw

The arms are those of the barons of Longueuil (the first, Charles de Moyne, figures in the story), and today these arms are used by Longueuil, Quebec:

http://archive.gg.ca/heraldry/pub-reg/ProjectPics/iv372_20020027_arms_longueu.jpg

The CHA register notes that this use is with the permission of the current baron, a descendant through the female line.

Best 26 cents I ever spent.

Congratulations Mr. Thornton!