grave quilts

Friends are visiting from Massachusets, so I am out seeing the sites. One of my favorites is the cemetary in Eklutna Village. Most of the graves are covered with Athabaskan "spirit houses", painted bright colors every spring. (Jim says it reminds him of a minerature golf course.)
Other graves are covered with blankets or quilts weighed down with rocks. We need a quilt anthropologist here! It looks like the top of the quilt disintegrates first, then the batting, then the bottom. Here is one example, with just a fragment of fabric left. I suspect, from the size of the fabric scrap, that the quilt was placed on the grave pieced side down.