What is on the other side of that wall, is that a crawl space? I would clean the dirt up and try to see where it is coming from, there is no way for us to tell from the video, at least not myself.
Ayuh,.... What sorta old mill stone,..??That wall represents the right side of the house - 1890s construction. So for all i know that is old insulation that has distinigrated possiby. The exterior is old mill stone w/ what should have been a lathe aand plaster wall.
Lord knows some creature was having a good time back there,, i'm tempted to fill w/ rocks and concrete, then call it a day. I'll post more pictures when i get it cleaned up. thanks :thumbsup: