Late Silurian Graptolites from the Bainbridge Formation in Southeastern Missouri

New graptolite collections obtained from the upper part of the Bainbridge Formation in the type section and in three new stratigraphic sections in southeastern Missouri have yielded numerous specimens of Monograptus ulrichi (Ruedemann), Monograptus angustidens Přibyl, monograptids of the M. dubius (Suess) type, and linograptid fragments. The presence of M. angustidens suggests Late Pridoli age (latest Silurian) age for the beds from which it came. The other graptolites are indicative of an age in the span of late Ludlow through Pridoli for the layers bearing them. Fossil and lithologic aspect data indicate that the shales and thin-bedded limestones that constitute the upper part of the Bainbridge Formation in southeastern Missouri and southwestern Illinois range in age from early Ludlow through Pridoli, that is, through the Late Silurian.