Hundreds of years prior to the 22nd century, a set of katric arks was discovered at the P'Jem monastery. The arks were scanned and analyzed, and one of the scientists even attempted to initiate a mind meld with them, all to no effect.
In 2137, Syrran, leader of a Vulcan dissident movement, discovered the ark containing Surak's katra on Vulcan. Syrran was successful in transferring Surak's katra to his own mind, successfully carrying it until his death in 2154, at which time he transferred the katra to Jonathan Archer, a Starfleet captain. (ENT: "The Forge", "Awakening")
In several Star Trek novels, such as The Lost Years, the katric ark facility is a chamber within Mount Seleya known as the "Hall of Ancient Thought". In the Hall are thousands of receptacles (vre'katra) containing the katras of the greatest and most powerful Vulcan masters throughout history. Vulcan scholars, philosophers, and mystics could petition to be permitted to meld with these katras for research or enlightenment.