Mystery cartridge -- help identify?

Perhaps this list can help me identify something I just picked up. It's a white plastic cartridge with a 44-pin male card-edge connector and a light blue plastic female passthru for the same type of connector. It has a square black plastic button on top. It is (was) glued shut. Inside there is an 24-pin EEPROM (88251A+ MM2716Q) with a Mitsubish Electric sticker covering the window, a 14-pin IC (P234 DM7400N), and another 14-pin IC (EL SALVADOR 1820-0328 7936 <Texas Instruments Logo> SN7402N). And two small resistors and capacitors. On the circuitboard it says "NAVARONE (C)" and next to the contacts where the little carbon pad on the underside of the button makes contact, it says "TOP". It looked about the right size for a C64 cartridge, but it doesn't do anything. Any ideas? Too bad I pretty much destroyed the case while opening it. It was glued shut pretty tight. -jrs _______________________________________________________________________ \/|/\ | Jason Simpson | http://www.xio.com/jason/ /\|\/ | jason(a)xio.com | Wanted: '87-90 Volkswagen Fox 2 Door Wagon