FAMN Geology class, hike and more

Ask a Master Naturalist  

By Robin Harris 

In the pre-dawn hours of Saturday I headed out to pick up my new friend Grace to accompany me on a journey from Heber Springs to Petit Jean State Park for another Arkansas Master Naturalist day of learning. The drive was long and beautiful up steep curvy roads, over the Arkansas River, up the mountains and down, and past fields of not yet planted abundance. We passed herds of deer snorting steamy breath and stomping their insult of the intrusion on their quiet grazing in the sun threaded forest until we finally passed the park entrance sign. 

Rising 1,120 feet above the Arkansas River Valley, Petit Jean became the first state park in Arkansas in February 1923. There wasn’t a state park system in Arkansas so Petit Jean Park was managed by the State Highway Commissioner. In 1927 a State Park Commission was created. They had the funding to proceed with Arkansas park development. The formation of the Civilian Conservation Corps (CCC) built the structures and trail systems in the park. Today our group met in the CCC barracks for our class and explored parts of the park in the afternoon. 

In the morning Darcia Routh, Geology Supervisor for the Arkansas Department of Health taught us all about Arkansas Geology and Ecoregions. Darcia’s specialty (at the moment) is source water protection. She is a 9 year Certified Master Naturalist of the first Arkansas Master Naturalist Chapter out of central Arkansas (formed in 2006), former LSU career instructor, petroleum geologist, and chaplain. Darcia not only explains things in an interesting way, she has a great sense of humor. 

The Geology class taught the group about Arkansas’ six divisions; the Coastal Plain, the Ouachitas, Mississippi Alluvial Plain, Arkansas River Valley, Crowley’s Ridge (glacial flour), and the Ozarks. Each area has unique geology and ecology. For instance, in the Ouachitas, the south slopes are warm and dry, and primarily pine forests whereas the north slopes are cool and moist with hardwood forests. Crowley’s Ridge is 250-550 feet tall and runs in a line for 150 miles. It has unique vegetation including the rare Tulip Tree. The Mississippi Alluvial Plain is fairly flat due to erosion and deposition from rivers and streams. The Arkansas River Valley is 40 miles wide and runs 140 miles E-W across the middle of the state. It has formations resembling the Ozarks dissected plateaus and Ouachitas folded ridges, yet it has unique mesas, and Petit Jean Mountain. The formations in the Ouachitas were folded (bent or curved) and in the Ozarks they were uplifted long ago in geologic time.  

In the afternoon the group went to the Cedar Falls overlook and down the Boy Scout Trail. This trail has representation of all the habitats that make up the park’s ecosystem. Darcia explained the differences in turtle rocks and carpet rocks. She showed us various things in the Hartshorn Sandstone such as iron banding and cross-bedding. Afterwards, the group went to the Rock House Cave accompanied by Certified Master Naturalist, Don Higgins USAF, Retired (amateur archeologist and rock art expert) who explained that this is not really a cave it is a rock shelter that has Native American rock art created 8000 to 400 years ago. Some of these same markings have been found in Texas along the Red River. The cave drawings were created out of iron oxide powder from the banding or iron oxide powder mixed with water or mud or fat and boiled to make different colors. There also have been some discoveries of pottery high upon a shelf near the ceiling. This shelf is believed to have been used for storage, it is cool and dry and animals cannot reach it. The climb out was vigorous but we made it to the top. Hugs and handshakes and the day was done.  

Grace and I surrendered our tired bodies to the car and drove home towards the pink and yellow clouds clinging to the sunset. Another rewarding day with the Arkansas Master Naturalists. 

Have a question? Email it in to ArkMNaturalist@gmail.com – we will try to include it in our next column. 

Photos by Phil Wanzer, Sharon Furgusson and Larry Fliss


See more photos at


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