Middlesex County Public Schools Superintendent Dr. Peter Gretz is leaving to become the head of the Fluvanna County Public School System. The Southside Sentinel reports the board accepted Gretz’s resignation on Wednesday and it takes effect on June 30. In an e-mail to the district Gretz said he could not have asked for a more supportive, thoughtful and deeply caring school board or a more talented, committed and inspiring group of colleagues to have shared this journey.