Perhaps Arab- Pseudo Byzantine, not unlike the following, which is also "Overstruck on an older clipped follis (typical for the type)":
http://www.forumancientcoins.com/ca...g=38141&fld=http://www.forumancientcoins.com/Coins2/
http://www.forumancientcoins.com/ca...g=38141&fld=http://www.forumancientcoins.com/Coins2/
























