A Norfolk County Agricultural High School teacher has been placed on administrative leave after his arrest for allegedly walking in his driveway wearing only ski goggles and a knit cap, according to a school official. Marc Mertz, 44, pleaded not guilty in Wrentham District Court to charges of open and gross lewdness and disturbing the peace, according to Deputy Police Chief John Carmichael. He said the charges stem from incidents on Jan. 20, Martin Luther King Day, when two women driving on North Street separately reported seeing a man standing naked — except for ski goggles, a hat and, briefly, a towel — in the driveway of a home. Police located Mertz, then wearing a towel, at the home and arrested him on a warrant two days later, Carmichael said. “There was no sign that he was on drugs and there didn’t seem to be drugs involved,” Carmichael said. “It was just kind of an odd situation.’’ Mertz is listed as teaching in the plant, environmental and mechanical technology department of the regional school on Main Street. Superintendent Suzanne Green said because it was a personnel matter she could not say anything except that he had been placed on administrative leave.