Robuta

https://popups.ulg.ac.be/1374-8505/index.php?id=3140&lang=nl Trace element variations in the Middle Frasnian punctata zone (Late Devonian) in the Western Canada... in the middle trace element late devonian western canada variations https://popups.ulg.ac.be/1374-8505/index.php?id=6966&lang=fr Frasnian reef mounds in the Durbuy–Bomal area (eastern border of the Dinant Synclinorium, Belgium)... in the frasnian reef mounds area