Comment on: Orbital cyclostratigraphy of the Devonian Frasnian–Famennian transition in South China, by Gong, Y.M., Li, B.H., Wang, Y., Wu, Y., Palaeogeogr. Palaeoclimatol. Palaeoecol. 168 (2001), 237–248

The four-order orbital cyclostratigraphy scheme of the Frasnian-Famennian transition in South China of Gong et al. (Palaeogeogr. Palaeoclimatol. Palaeoecol. 168 (2001) 237) is criticized. Its dubious character is related to unreliable documentation of the four-order hierarchical Milankovitch cyclicity, paired with a highly speculative idea of modification of the causal orbital parameters in the mass extinction time interval by alleged bolide impact.