Leaves changing at one of my favorite leaf-watching spots in Spearfish Canyon, Long Valley. (Spearfish, South Dakota) In this video, you will first notice the shrubs changing from greens and yellows into reds and burgundies. Next, look along the Canyon walls, where deciduous trees change into their golden hues. Finally, along the roadway the birch and aspen pop out behind the evergreens and line the Scenic Byway. Long Valley showcases the Canyon’s diverse flora. But what makes this area extra special is the beautiful display of limestone as a backdrop to the fall foliage. I talked with a local geologist who shared that the top tier of Long Valley is Paha Sapa limestone that is 600 feet thick. Lower down we see lavender-colored Englewood limestone.