About 15 miles north of Ardmore, Oklahoma, Interstate 35 leaves the rolling horse country of southern Oklahoma and climbs across a broad ridge, now topped by a wind farm. Known as the Arbuckle Mountains, this ancient uplift is the erosional remnant of a tall mountain range that rose during the late Pennsylvanian and early Permian Periods, some 290 million years ago.
The core of the uplift, which is approximately 35 miles long and oriented ESE to WNW, is composed of Precambrian granite and gneiss, 1.4 billion years old. Flanking this core are volcanic and sedimentary strata, deposited from the Cambrian to the Pennsylvanian Periods. Permian sediments lap against the north edge of the Arbuckles while Cretaceous deposits abut the southern base of the ridge.
The highest elevations in the Arbuckle Mountains approach 1400 feet above sea level and are found near the western end of the range. The Washita River, a tributary of Red River, slices through the ridge SSE of Davis, Oklahoma, producing limestone cliffs that tower 350 feet above the valley floor.
