Last Wednesday, the California Coastal Commission signed off on the legal adequacy of Marin County’s most recent step in updating its Local Coastal Program, a process that began more than a decade ago. The county Board of Supervisors in April unanimously approved three of seven amendments to Marin’s L.C.P., which dates back to 1982 and identifies the ground rules for development in the coastal zone. Though the commission initially asked the county to approve the…