Hello: I found two piles of what looked like sand on the concrete basement floor. The only bugs I found in the basement are spiders (and many webs). It doesn’t look like dirt—it is debris from carpenter ants? Pavement ants? Terminates? Or something else? The basement is unfinished and used to store things. I saw the piles when getting Xmas decorations out. Any ideas of what this is? Thank you