Taken by my kind friend in the museum. Also confirmed against several specimens there that it's not a human clavicle. The mystery deepens...

'back'

'front'

'front' detail

'back' detail

upper edge

My current thought is porpoise vertebral process, since it seems too fine for seal (compared to grey seal reference), too small for pilot whale and not broad enough for cow...does anyone have any experience with porpoise bones? Turtles have washed up in Orkney historically, but I have no idea what their skeletons even look like.

My continued thanks,

~ Cecily