The Wet rock physa, scientific name Physella zionis, is a species of freshwater snail, an aquatic pulmonate gastropod mollusc in the family Physidae, the bladder snails. This species is endemic to two connected canyons, Zion Canyon and Orderville Canyon, along the north fork of the Virgin River in Zion National Park, Washington County, Utah, a stretch of about 5km (03miles) (Oliver & Bosworth 1999).
Oliver, G. V. and Bosworth, W. R. III. (1999). Rare, Imperiled, and Recently Extinct or Extirpated Mollusks of Utah: A Literature Review. Utah Division of Wildlife Resources. Publication Number 99-29.