Knowledge Bank

A stratigraphic section 100 m. thick of the uppermost Chagrin Shale was compiled for its exposures in the valley of Paine Creek, in Lake County, Ohio. It was possible to do this using siltstone "key beds." This section was sampled for conodonts. Conodonts were found to be scarce in the upper part of this section, and more plentiful 70 m. down in the section. The form genus Palmatolepis was not found, but the form genus Polygnathus was found in 6 samples, and included 4 or 5 species, including P. semicostatus and P. delicatulus. Simple cones were recovered from 7 samples, and what may be a new form of Pelekysgnathus was recovered near the top of the section. The Famennian age of the upper 100 m. was confirmed. Evidence was presented supporting the proposed shallow-water marine environment of deposition for the Chagrin Shale.