About 4 miles east, I-40 (Hwy 66) crosses one of the most recent lava flows in the continental United States. Indian pottery has been found under the lava, which first flowed about 4 million years ago from Mount Taylor, to the north. Lava also flowed less than 1,100 years ago from fissures that, today, are near the highway. The lava is sharp and hard; heavy shoes are advisable for walking on it. A Ranger District office of the Cibola National Forest is located here.