A natural area owned and managed by the Chihuahuan Desert Research Institute for scientific research and education. The facility includes an arboretum comprised of plants native to the Chihuahuan Desert Region and a cactus greenhouse. Modesta Canyon Trail is a self-guided nature trail to Modesta Springs, and Clayton Overlook is the highest point on the property. Signs along the trail point out geologic formations and give facts about plants and animals. Visitors to Clayton Overlook are almost always rewarded with a glimpse of aoudad sheep from the southwest slope of the mountain. On Texas 118, 3.5 mi. south.