RANGELEY – The Sunday nature program at Orgonon on the Dodge Pond Road on July 8 will be “Stonewall Secrets” with Ruth Deike.

Deike has a degree in geology and mineralogy. She moved to Maine in 1996 to enter a career in earth science education and she founded a nonprofit organization, Rock Detective Geo-science Education. Deike has authored “Stone Wall Secrets Teacher’s Guide,” which traces the geologic history of New England.

Participants will meet at 2 p.m. at the outdoor classroom on the Orgonon property for the free program.