What do I need to fix this. Galvanized roofing nails and tar???
Ridge vent or ridge cap?
Ridge cap: some shingles cut to size, some roofing nails and some roofing tar in a caulk tube.
Ridge Vent: cap if you didn't find the old one, longer nails, shingles cut to size.
For shingle over ridge vent you will need 3" roofing nails to install both the vent and the capping.
Roof ridge could mean any of a dozen differant things.
Is it metal, slate, shingles, shakes?