The little fly-sheet of Zorn l - for it is scarcely more - on the birds of the Hercynian Forest made its appearance at Pappenheim in 1745.
The principal folding took place at the close of the Carboniferous period, and was contemporaneous with that of the old Hercynian chain of Belgium, &c. The Permian and later beds lie unconformably upon the denuded folds, and in the space between the Montagne Noire and the Cevennes proper the folded belt is buried beneath the horizontal Jurassic strata of the Causses.
It is the " Hercynian chain " of Marcel Bertrand, and is composed entirely of Palaeozoic rocks.
The whole mass evidently belongs to the ancient Hercynian chain of North Europe (which, indeed, derives its name from the Harz), and is the north-easterly continuation of the rocks of the Ardennes and the Eifel.
The "Hercynian " earth-movements, which so profoundly affected north-west and north-central Europe at the close of Carboniferous times, gave rise to a series of east and west folds in the Irish region.