These are extremely rare and collectible strikes--the $10 Caesar's Palace undated GDC Roman Coliseum and the $10 Caesar's Palace undated GDC Chariot.

To see what this pair looks like, go to the Silver Strikers website, then in the catalog look at the top two scans on the Caesar's Palace page.

Mine were acquired in 1998 when it was believed that there were five known sets.

I'm no longer collecting and would only be interested in selling, not trading. If you're interested, please email me off-list.