Abstract: Pterosaur fossils are rare in the Morrison Formation, and most are poorly preserved. The Breakfast Bench Facies (BBF) at Como Bluff produces incomplete but uncrushed limbs. One proximal and two distal femora match a complete femur (BYU 17214) referred to Mesadactylus . Unexpectedly, both of the BBF distal femora possess a large intercondylar pneumatopore. BYU 17214 also possesses an intercondylar pneumatopore, but it is smaller than in the BBF femora. Distal femoral pnuematicity is previously recognized only in Cretaceous azhdarchoids and pteranodontids. A peculiar BBF jaw fragment shows strongly labiolingually compressed, incurved crowns with their upper half bent backwards; associated are anterior fangs. We suspect this specimen is a previously undiagnosed pterosaur. Additional BBF material documents a diverse pterosaur fauna including a humerus with a greatly expanded ectepicondyle possibly from a non-pterodactyloid monofenestratan.

Abstract Geological and human forces have created some spectacular treasures at the boundary between the Central Lowlands and the Great Plains, and three of them are explored in this guide. In northern Nebraska, the Ashfall Fossil Beds site, a world-class Lagerstätte of articulated mammal, reptile, and bird skeletons, reveals the mass death of a Miocene biotic community. Chapter 1 provides a detailed overview of the geology, paleontology, and reconstructed paleocommunity at Ashfall. The bluffs of the Missouri River in eastern Iowa contain some classic type sections of Pleistocene stratigraphic units. Chapter 2 explores the historical development of Pleistocene stratigraphy in this area and presents new data to refine understanding of the area’s complex geological history. Finally, Chapter 3 presents a unique tour of the Nebraska State Capitol in Lincoln, which is clad with Indiana limestone and adorned with igneous, metamorphic, and sedimentary rocks from European and U.S. quarries. The field guide describes the historical, architectural, and geological aspects of these stones.