Strata of the Chinle Formation (IMAGE) Geological Society of America Caption Strata of the Chinle Formation below the prominent silcrete horizon exposed in the Petrified Forest National Park. Credit Photo courtesy of Andrew V. Kearns, 2012. Usage Restrictions GSA Bulletin; photo courtesy of Andrew V. Kearns, 2012. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.