Identifying strange old insulation in house walls?

I had to cut a large access hole in an inside wall in my house, built in 1930 and heavily "remuddled" in the 50's and 60's. We needed to get into the enclosed attic headspace to evaluate the roof framing to install solar panels so I cut into the space above the stairs to the second floor. When I cut through the lathe and plaster I found insulation batting on the inside of the cavity. I have worked in construction for 35 years but never saw batt insulation like this. It has a "skin" that was sort of like a lightweight black tar paper and the insulation materiial itself is layers made up of thin crinkly brown paper-like material with tiny pleats in it. The best I can describe it is that it reminded me of baklava pastry. I don't see any asbestos or glass like fibers in it and it doesn't look like any cellulose material I've ever seen, but it did tend to crumble when I removed it from the wall and bagged it for disposal. I used gloves and a respirator while pulling it out and vacuumed up with a HEPA filter afterwards, but I'm just curious what the material might have been. Any remodellers or insulation pros on here that can tell me what this stuff is and what cautions I should take in removing it?