Rillito River. There was a continuing effort to purchase land for future school sites in the face of rising land costs in the foothills of the Santa Catalina Mountains. In 1955 a parcel northwest of North Oracle Road and West Ina Road cost the district $7,000 and was considered too far north and too costly. The parcel became the site of Winifred Harelson School in 1960. In 1958, Lawrence W. Cross became the assistant superintendent for the district. The construction of Walker School in 1963 north of the Rillito River brought the "open classroom" and educational innovations to the district under the leadership of Evelyn Carswell as principal. The concept for learning at Walker School was focused on the individual student and individualized schedules, small and large group settings, and an ungraded school. These innovations brought national attention to the Amphitheater District, but eventually these changes were perceived as too radical and a return to more traditional educational structure was the final outcome. Beginning in the fall of 1962, the Canyon del Oro School opened at the base of Pusch Ridge in the Santa Catalina Mountains serving as a middle school and later the district's second high school (beginning in the fall of 1964). CDO's first graduating class was in the summer of 1968. Population growth continued in the district as additional schools opened. By 2001, the district opened a third high school (Ironwood Ridge High School) to meet the growth needs in Oro Valley and the north side of the district. At present, Amphi has a current enrollment of about 13,500 students across the district. Only Tucson Unified School District and Sunnyside Unified School District enroll more students in the Tucson metropolitan area. Amphi is an economically diverse district, serving disadvantaged communities in North Tucson, and affluent communities in Oro Valley and the Catalina Foothills. Nine-year-old Christina-Taylor Green, a student at Mesa Verde Elementary, died in the 2011 Tucson shooting. The school provided grief counselors in response to the event. Note: The Wetmore family and L. M. Prince were both featured in David Leighton's popular weekly column, Street Smarts, Sept. 18, 2012, and August 20, 2013, in the Arizona Daily Star newspaper. District schools The following schools are part of Amphitheater Public Schools: References External links David Leighton, "Street Smarts: Wetmores had deep roots in north-side area", Arizona Daily Star, September 18, 2012 David Leighton, "Street Smarts: Prince Road