Yesterday I went on a walk. The trail, used by both walkers and bicyclists, is part of Lilydale Regional Park, on the south bank of the Mississippi River a bit upstream from downtown St. Paul. (The Mississippi flows towards the NE as is passes downtown St. Paul.) The trail led past an old brickyard, around the base of a fossil bed, and past caves that were once used for mushroom-growing and cheese-making. According to one of my walking companions, it was also a swell place for gangsters to hide in the 1930’s. I was on the lookout for textures … and fascinated by the geological as well as human history of this area. There are 3 primary geological layers here — St. Peter Sandstone at the bottom, Platteville Limestone above that, and then Decorah Shale on top where the fossils are. NOTE: (added 8/12) An optional ingredient in rice paste resist is calcium hydroxide, or lime. A small amount of this highly alkaline ingredient can help give the paste a bit more elasticity. John Marshall notes that if you live on large limestone deposits you probably don’t need to use it because it comes out of the tap.