The link below will take you to the cover of the French release of THE TOYNBEE CONVECTOR. The collection was published in France by Denoel as A L'OUEST D'OCTOBRE (which translates in English to WEST OF OCTOBER). I know that's Hamlet on the cover, but alas that sure doesn't look like Yorick's skull he's holding!

https://www.isfdb.org/wiki/ima...e/LSTDCTBRHF1989.jpg