Catalog Number
Unity Roller Mills Advertisment, n.d. On the front it states, "Compliments of H. Keppel & Sons, Unity Roller Mills, Dealers in Flour, Feed and Grain. Zeeland, Mich. There are horses, cows and sheep on the from with a barn in the background.
The firm of Boone & Co. Owned a sawmill in Holland near Zeeland, possibly in the village of Groningen. The Boone family hauled timber to Black River, loaded it on flatboats, and piloted these through Black Lake (Lake Macatawa) to Lake Michigan, where the lumber was shipped out for manufacture into barrel staves. A Holland City News item of August 7, 1880, relates that the Boones recently purchased a small steamboat, the Mud Turtle, to aid their enterprise.

Unity Roller Mills of Zeeland was also known as Unity Flouring Mills. The company was founded by Huibert Keppel, a first-generation settler of Zeeland. Huibert made his son, Govert, co-owner under the umbrella firm of H. Keppel & Son. No firm dates for the founding or closing of the millworks can be established.