After figuring if it is c-41 (has mask) or not, you then have the chance of it being slide film, if yiu cannot make sense of what the date codes on the side are.
See if a local lab will process a small few frames piece that you have shot; if slide it will cross process to yeld wierd ( and sometiems attractive) colours; if not, and it is b&w a bit might end up as sludge in thier filters, if the b7w emulsuion slides off the support if it is a non hardended gelatine variety.
If b&w, and still not edge marked then shoot test patches as found in old Kodak data guides or MacBeth charts at different exposure values that meter correctly at ISO 12, 25, 50, 100, 200, 400 using a grey card to determine the metered exposure. The first exposure that gives you printable differentiated tone between the two blackest targets will give you your effective EI, and then it is a matter of exposing for white at that ISO and seeing how long to develop for to nail the parameters for you. This is straight from memory, learned from a little gery book that Fred Picker put out that tought me that what the manufacturer said on the box may not work best for you. In this case you can't be mislead by the box.
If it turns out to be lower than 12 iso, then suspect you might have ortho lith, which was most commonly available in 100' lengths.