Crossword Puzzle Prefix meaning ''stone''

Clue: Prefix meaning ''stone''

It equals 0.3937 inch (CENTIMETER with 10 letters)
39th president of the United States (JIMMYCARTER with 11 letters)
Alma mater of the 39th Pres. (USNA with 4 letters)
Super Bowl to be played in the year 3968, at the current rate (MMII with 4 letters)
39th VP (AGNEW with 5 letters)
39th vice president (AGNEW with 5 letters)
Favorite Hall of Famer of the 39th U.S. president? (GARYCARTER with 10 letters)
39th Veep (AGNEW with 5 letters)
39th V.P. (AGNEW with 5 letters)
39th of 50 (NORTHDAKOTA with 11 letters)