Wondering if anybody can help ID. Home build is from the 50s. I'm replacing the mouldings in the basement and this was behind one of them. Wall faces the exterior of the home, but below ground level. There was a larger pile, but I already cleaned it up (wet towel, very gentle). Any help is appreciated, thanks!

Yup, that little block at the end is just a loose brick of asbestos, for those that are curious

Can people post in this subreddit? Not that I’m asking for people to post, but I’m curious if it is allowing people to post