Here's a comment by Donald N. Riemer in his Turtles & tortoises on stamps list, concerning a turtle stamp from Mactan Island:
"Cinderellas produced at a U.S. airbase on Mactan Island by Mr. Cyzl who was stationed there. Perfs were added when Mr. Cyzl returned to the U.S. Available perf. and imperf."
MACTAN ISLAND (local name OPON) - Personal Psuhttp://personal.psu.edu
› update.0212 › countries › MA
(hope that works)