DIASTROPHISM AND THE FORMATIVE PROCESSES 341 



the close of the Carboniferous, together with great eruptions of 

 igneous rock which were presumably associated with the move- 

 ments.^ 



PERMO-CARBONIDES 



In the two preceding sections an endeavor has been made to 

 separate the Culmides and Westphalo-Carbonides out of the great 

 group of diastrophic movements that marked the close of the 

 Paleozoic. It remains to assemble the movements that took place 

 following the Permo-Carboniferous sedimentation. But here the 

 time of the diastrophism can be less definitely located, and the 

 correlations less closely made than in the case of the Westphalo- 

 Carbonides. Recognizing this difficulty the term Permo-Carbo- 

 niferous is quite widely in use in various parts of the world, and 

 as this is in reahty a period of transition from the Paleozoic to the 

 Mesozoic, this terminology has its advantages, and the name 

 Permo-Carbonides will be used to designate the final set of dis- 

 turbances which mark the break between the two eras. 



One of the most familiar as well as one of the most pronounced 

 of the Permo-Carbonide movements was the folding of the Appa- 

 lachian Mountains of North America. The principal folding of the 

 Appalachians followed the laying-down of the Dunkard sediments, 

 which are the youngest strata involved in the folds. The age of 

 the Dunkard beds was identified as Permian by Fontaine and 

 White in 1880,^ and this has been very commonly accepted since. 

 But David White states that the flora of the Dunkard shows it to 

 be transitional between Carboniferous and Permian, and that its 

 uppermost portion corresponds approximately to the lowest mem- 

 ber of the Rothhegende of Europe.^ This reference of the greater 

 part of the Dunkard to the Lower Rothhegende he believes to be 

 well founded. This would bring the main folding of the Appala- 



^ Bailey Willis, Research in China, I, Pt. I i^-9o^), 297. 



2 W. M. Fontaine and I. C. White, "The Permian or Upper Carboniferous Flora 

 of West Viriginia and Southwestern Pennsylvania," Second Geol. Sttrv. of Pennsyl- 

 vania, Report of Progress, PP. (1880), pp. 105-20. 



3 David White, "Permian Elements in the Dunkard Flora," Bull. Geol. Soc. Am., 

 XIV (1903), 538-42. 



