Day One Rivertrek 2017

Means Creek, Day One Rivertrek 2017, by Harley Means

We met the Rivertrek group at the confluence of Means Creek and the Apalachicola River. The group hiked up a limestone escarpment and headed east. Along the way we observed limestone cropping out near the surface and saw several sinkholes as we neared the caves. At the entrance to the cave we discussed the local geology.

Karst topography has formed in this area as the result of dissolution of the Chattahoochee Formation, the limestone unit that is exposed in this area. This limestone is early Miocene (~20 million years old) and was deposited in a shallow, warm marine environment when sea level was higher. Over millions of years acidic rainwater has dissolved some of this limestone, leaving behind void spaces that later collapsed, forming the sinkholes and caves we explored. After crawling through the cave, we all hiked down and got into the bed of Means Creek.

Means Creek is unique in that it has incised down into the Chattahoochee Formation and carved a mini slot canyon! In places, the canyon is 20 or more feet deep. The walls of the creek are bare in areas where the water has scoured and covered in ferns and other plants in places where water has not yet reached. Small seepage streams and ledges have formed along the creek as we walk toward the Apalachicola River.

Fossils are not common in the Chattahoochee Formation, but we were lucky to find an area where dugong bones are eroding out of the bank of Means Creek. These bones belonged to a marine mammal that lived in the shallow seas that existed in this part of Florida more than 20 million years ago. Dugongs are related to manatees, but they no longer live in Florida.

Harley Means, geologist, P.G. is Assistant State Geologist at the Florida Geological Survey

Here some of the species identified during the hike, by Ryan Means

• Apalachicola Dusky Salamander (Desmognathus apalachicolae)(named by my Bruce Means in 1989), found only in  N.  FL, SW GA, and SE AL.  In FL, it is found on the east side of the Apalach River in  the ravines.
• 2-lined salamander (Eurycea cirrigera)
• Long-tailed  salamander (Eurycea guttolineata)
• Cave crickets (or camel cricket) in the cave (Family: Rhaphidophoridae)
• Means Creek is the most prominent  Florida “slot canyon” creek in  the  state that I am aware of. It slices through the Chattahoochee Formation  limestone (ca. 20 million years  old).

Biologist Ryan Means is co-founder of Remote Footprints and director of Coastal Plains Institute