Hey folks: I have a cottage on the Sauble River not far from Lake Huron. I am an English teacher and Chaplain but I have always been interested in the science of the world around me. At the bottom of the river there are rock "shelves" that are fragmented and this sedimentary stone (?) broke away. I flipped it over and saw this shape. There were actually two but I am conscious of file size. My rookie guess is a crinoid stem but better to ask the experts. Thank you in advance! Jon.