Article: Some Upper Tremadocian graptolites from Norway

New material of Upper Tremadocian graptolites from the Oslo Region, preserved in full or half relief in pyrite, is described. Bryograptus ramosus Brogger 1882 is shown to have distinct bithecae. 'Didymograptus' kiaeri Monsen 1925 is also shown to have bithecae and is made the type of the new genus Kiaerograptus. Adelograptus bulmani sp. nov. is a peculiar species, which might have affinities both with the anisograptids and the leptograptids and might be intermediate between them. The presence of bithecae in some graptoloid-like forms in the Upper Tremadoc suggests that the presence of graptoloids in beds older than the Arenig might be questionable. The material present might indicate that a number of graptolite lineages are more complex than previously assumed, and that several lineages in the dichograptids and other graptoloid groups originated directly and independently from the dendroids.