Subject ASC000116o
The Quarterly journal of the Geological Society of London.
v.56 (1900), Page 483 (1900)
Smithsonian Libraries
BHL Page 41487839
Keywords
graphtolite fossil invertebrate graptolite River Irfon Elton-Ludlow Road sicula Builth Nicholson Monograptus Prof. Frech Barrande heca polypary Dee Valley historical taxonomy paleontology sylurian plants Lower Ludlow graptolites fauna Bohemicus thecae theca polypary