Common on white bluffs trail, only a few starting to open flowers.
Substrate was gravelly/sandy/rocky. More clearly visible in https://www.inaturalist.org/observations/208551382 and https://www.inaturalist.org/observations/208553280, which were not far away.
Not sure if this is the exact variety, but how cheerful to see the riverbank filled with sunflowers on a sunny Sunday afternoon