While doing some research in Google Books, I found an item in the May 1913 issue of Santa Fe Employees' Magazine that described the burial of a 100-year time capsule:
A unique service was held on April 22 at the Lutheran Church in Oklahoma City, Okla., when a copper chast containing phonograph records of speakers and singers, writings, musical compositions, daily newspapers and many other records of current events was buried. It is to remain intact until the year 2013, when it will be opened and the gap of a century will be bridged; and the future generation will hear the voices of our great men of today and read the writings and papers which we read today. The event was to celebrate the twenty-fourth anniversary of the opening of Oklahoma for settlement.
Sometimes time capsules are forgotten, but that's not the case here. The leaders of First Lutheran Church recently found the capsule with ground-penetrating radar and will be unveiling the contents of the Century Chest on April 22 as planned. The congregation gathered once a year at the time capsule's burial site and pledged to remember it. "They didn't want this to be forgotten, and it won't be," said Chad Williams of the Oklahoma Historical Society.