Physical Sciences and Mathematics Commons^™

Late Tertiary Rodents From The Catamarca Province, Argentina : The Field Museum Collections, Lee A. Schremp

Loma Linda University Electronic Theses, Dissertations & Projects

The rodents collected in the 1920's by the Marshall Field Expedition for the Field Museum of Natural History, Chicago, are systematically reviewed and placed within the stratigraphic framework established at the time of collection. One new genus (Proeuryzygomys) and three new species (Abracoma intermedias, Proeuryzygomys diminutiva, and Cayiodon (Lelongia) catamarcensis) are proposed. Two distinct faunas are recognized corresponding to the Huayquerian and Montehermosan Land Mammal Ages respectively. Several computer programs were developed to aid in character analysis.

Palynology And Age Of The Alvord Creek Formation, Steens Mountain, Southeastern Oregon, Stephen F. Barnett

Loma Linda University Electronic Theses, Dissertations & Projects

The age of the Alvord Creek Formation of Steens Formation, southeastern Oregon, has been a center of controversy since Axelrod's 1944 paleobotanical assignment of a Lower Pliocene age to the tuffaceous leaf-bearing shales. This date varies from earlier determinations by Chaney and MacGinitie that the flora was Mascall (Upper Miocene) equivalent. However, it is more sharply contradicted by the report of a Middle Miocene (Barstovian) fauna in the apparently overlying Steens Basalt and by a 21.3 m.y. radiometric date obtained on a basalt flow 61 meters above the leaf-bearing beds.

Palynomorphs recovered from three exposures of the leaf-bearing beds show …