TRILOBITES, BIOSTRATIGRAPHY, AND LITHOSTRATIGRAPHY OF THE CREPICEPHALUS AND APHELASPIS ZONES, LOWER DEADWOOD FORMATION (MARJUMAN AND STEPTOEAN STAGES, UPPER CAMBRIAN), BLACK HILLS, SOUTH DAKOTA

ADDITIONAL INFORMATION ON LOWEST ORDOVICIAN TRILOBITES FROM THE UPPERMOST DEADWOOD FORMATION, BLACK HILLS AND BEAR LODGE MOUNTAINS, SOUTH DAKOTA AND WYOMING

Trilobites from the Cedarina dakotaensis zone, lowermost part of the Deadwood Formation (Marjuman Stage, Upper Cambrian), Black Hills, South Dakota

Trilobites from the upper part of the Deadwood Formation (upper Franconian and Trempealeauan stages, Upper Cambrian), Black Hills, South Dakota

Upper Cambrian and lowest Ordovician articulate brachiopods from the Arbuckle and Wichita Mountains, Oklahoma

Ptychopleurites spinosa, a new trilobite species from the Upper Cambrian of Texas and South Dakota

New Elvinia Zone (Upper Cambrian) trilobites from new localities in the Collier Shale, Ouachita Mountains, Arkansas

Cambrian-Ordovician boundary interval extinctions; implications of revised trilobite and brachiopod data from Mount Wilson, Alberta, Canada

Redeposited Elvinia Zone (Upper Cambrian) trilobites from the Collier Shale, Ouachita Mountains, west-central Arkansas

Jujuyaspis borealis and associated trilobites and conodonts from the Lower Ordovician of Texas and Utah

Enrolled Late Cambrian trilobites from the Davis Formation, Southeast Missouri

Ditomopyge scitula (Meek and Worthen) from the Lower Pennsylvanian of central Missouri and central Texas

Magnesium oxychloride; an excellent replicating material

Repeating evolutionary pattern in late Cambrian trilobite biomeres