You know I love an old school slate, but it's a rare occasion I come across one with a frame as beautifully primitive as this one, pine I believe, which has accrued the  warmest and richest dry patina over the past 150+ years. Many of the old school slates one sees were made in England, but this I am certain is American, found in Maine, all original, one small square iron nail next to one larger one at each of the jointed corners. Very sturdy and sound, with MH carved into one long edge of the frame on one side, and plenty of other little carve marks here and there. 

10 1/8" x 7 7/8" and in beautiful antique condition. Super rich patina, very sturdy and sound. With two holes in the frame at top for threading to hang if desired.