Building Fences: Post Rock for Rock Fence Posts

Enlarge Image Image Gallery Larry Rutter, who demonstrates post rock preparation, displays an antique hand drill used to bore holes into limestone slabs.

Imagine yourself as a 1880s homesteader on the vast, treeless expanse of the north-central Kansas prairie. As a soon-to-be farmer, you are responsible for protecting your property from range animals, for by law, cattlemen may graze livestock on all unfenced homesteads. You must erect a fence to lay claim to your parcel of land. But how? You need fence posts, but few trees grow. Lucky for you, the region is filled with a limestone rock layer from which you can make stone fence posts. Today that rock is known as “post rock.”

Limestone: the post rock

“The slabs are flat as can be, like a dance floor,” says post rock expert Larry Rutter of Meriden, Kan. “It has fissures and cracks, but it is extremely smooth.” Larry is retired from the Kansas State Historical Society and has demonstrated post rock preparation for nearly 20 years.

The rock is a chalky limestone in the “upper Greenhorn formation” of the Cretaceous Age, a geologic period that existed 60 million to 130 million years ago. Larry says slabs are found near the surface, covered by a soil layer called “overburden,” or even exposed on many bluffs throughout the Smoky Hills. The stone layer is usually 8- to 12-inches thick – ideal for masonry – and damp when first removed from the ground, which is the best time to shape it. After exposure to the sun and air, the limestone dries and becomes extremely hard.

Retrieving the heavy stones from the ground is a relatively straight forward process. Quarry workers use a simple set of tools: feathers, wedges, chisels, hammers, crowbars and hand drills.

“The way these stones are retrieved from the ground is not unique to Kansas or the post rock,” Larry says. “The same method was essentially used by the ancient Egyptians to build the pyramids. The earliest posts, however, were quarried with sledgehammers by the first settlers and hammered out to make buildings; a very labor-intensive method.”

Post rock territory

No one knows exactly when the first post rock fence was erected, but 30,000 to 40,000 miles of it were estimated to have been built in Kansas, according to a 1949 report in the Rush County (Kan.) News. The rock proved to be a very useful commodity because of its natural abundance and resistance to prairie fire.

Post rock territory stretches about 200 miles in an elongated oval across Kansas, from the Nebraska border southwest to just north of Dodge City. Ranging east to west, the boundary zigzags to varying widths, but roughly covers 5,000 square miles, or more than 3 million acres. According to a 1975 book, Land of the Post Rock by Grace Muilenburg and Ada Swineford, it is possible to find rock posts fashioned similarly in other areas of the world but not in the abundance and as extensively as in this region.