PAWHUSKA — In 1915, oilmen James A. Chapman and Horace G. Barnard, a pair of Texans from Waxahachie, purchased land in Osage County, Oklahoma. Over time, the ranch grew to more than 100,000 acres of tallgrass prairie with big blue-stem and switch grass growing so high cowboys would say “a man on horseback could get wet to the waist riding through the morning dew.” As time passed, parcels were…