A single library entrance from the Brickyard was opened in 1971. In 1972, the student union moved into Talley Student Center, and the Erdahl-Cloyd Union became the West Wing. It was connected to the East Wing by the new 10-story (numbered G, 1–9) Bookstack North Tower; opened on March 5, 1971, it added space for 1.2 million volumes and added 900 seats, 50 study carrels and 70 locked research study rooms. Coinciding with the 83rd anniversary of NC State's founding, the North Tower was dedicated on October 3, 1972. Previously, the library had had closed bookstacks, which were opened to all students following the construction of the new addition. In 1973, library holdings passed 600,000 volumes, and N.C. State became a charter member of the Southeastern Library Network (SOLINET), now LYRASIS.