, Melnichnaya Regional Stage, Katnikov Beds, Lochkovian Stage.
Trewin and Davidson (1996) considered that Pterygotus anglicus found in Early Devonian
rocks of the Midland Valley of Scotland spent their whole life in fresh water.
Waters said that as plant communities expanded onto land to form the first forests, they depleted the carbon dioxide (CO2) that was in the atmosphere, asserting that CO2 levels dropped to 400 ppm toward the end of the Devonian
Only 16 species, commonly represented by single specimens, of Silurian and Devonian
scorpions were recognised in 15 genera by Jeram (1998).
This outcrop was mapped as Upper Devonian
Ohio Shale by Reidel (1975) and lies stratigraphically above (immediately downstream of) a Middle Silurian dolostone.
Medium-crystalline, often cavernous dolomitic rocks occur only in the basal part of the Devonian
The young Paleozoic stage consists of Devonian
rocks, which discordantly overlie the Silurian rocks.
Records at these sites suggested that the Late Devonian
saw a prolonged drop in echinoderm diversity consistent with a mass extinction.
, New Harmony Group, subsurface Indiana
Overlying dark shales questionably placed in the Frame Member extend into the Early Devonian
Two outside operated Devonian
wells in the neighboring section have combined to produce 350 MBO and 3.
Boundary intervals of chronostratigraphic units are always significant for correlation purposes, and the Middle--Upper Devonian
boundary is no exception.