In the 1880s in mid-western Kansas, settlers quarried limestone to make stone fence posts from material deposited in a sea during the Cretaceous period about 70 million years ago. They drilled holes and then used wedges to quarry the stone, and each post could weigh as much as 300 to 400 pounds depending on its length. Fossil shells can be seen on the middle and right-hand posts. Because wood was scarce, settlers used the stone that was available.