Greetings everyone, my first post. I've attached a couple of photos of a rock I found recently that shows (to my untrained eye) what appears to be rows of raised bumps from some type of biological material. Or, maybe it is the result of something tunneling under mud or sand. Here's the data: found in the United States in the state of Utah, in Cache county, at the base of Little mountain, which is 2 miles north of the town of Newton. This area was under several hundred meters of water during the time of Lake Bonneville but I suspect that this example predates that era. The stone is textured on only one surface. The bumps are only 1 or 2 mm in height and I had to photograph the piece using low angle light in order to show the texture. The surface of the stone isn't perfectly flat but rather has some slight ridges and depressions and the imprint details follow those contours. Any thoughts as to what this may be, or what caused it, would be greatly appreciated. Thanks.