Hours: Visitor center open daily 8-6, mid-May to mid-Sept.; 9-5, rest of year. Access to the exhibit hall fall through spring is by car caravan. Visitors driving their own vehicles follow a ranger to the site; departures are at 9:30, 10:30, 11:30, 1, 2, 3 and 4. In summer, access is by a shuttle bus that departs from the Quarry Visitor Center on SR 149 every 15 minutes 9:30-5 (the last bus back to the visitor center departs at 5:30). Prior to 9:30 a.m. visitors may drive to the quarry themselves. Closed Jan. 1, Thanksgiving, Christmas and day after Christmas. Phone ahead to confirm schedule.