We were taking a hike today near the Great Miami River, north of Dayton, OH. We found a series of five primitive looking steel towers where some power lines cross the river. Instead of suspension insulators, these towers had a combination of large porcelain multipart insulators, smaller gray porcelains with the metalized radio treatment on top, modern plastic insulators and a single CD 257 "Mickey" on each tower but one. Do the towers themselves predate the era of suspensions?