In the gravels of the Mississippi in Wabash County, south of Minneapolis, agates formed in sedimentary rocks can be found. The specimen are showing a slightly yellowish or brownish color. The holey structure the agates are showing if the sediment between them is wheathered away  is interesting. This structure is a “look-alike” to silicified sponges. The agates are similar to those of Crowley Ridge, another finding-region for agates south to the Mississippi River in their pattern.