Pecopteris fern fossil. Pecopteris-leaved ferns appeared in the Devonian period,flourished the early Carboniferous period (Pennsylvanian) and on to c. 250 million years ago. They are named because of the regular comb-like arrangement of the leaflets. This example is from the Mazon Creek deposit,Illinois,USA and shows both positive and negative sides of a split nodule. These nodules are concretions of siderite or iron carbonate and naturally split along the middle | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library / Kidd, Geoff |
Bildgröße: | 3413 px × 5120 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |