. Bulletin - United States National Museum. Science. New Cretaceous Index Foraminifera from Northern Alaska By Helen Tappan ' Introduction STUDY OF ROCK SAMPLES from Naval Petroleum Reserve No. 4, northern Alaska, over a period of about 8 years has shown that among the microfossils occurmg in the Cretaceous strata are several new species which because of their stratigraphic importance should be described. Possibly because the strata here considered are of a facies distinct from that of the better known Cretaceous horizons (Tappan, 1951, pp. 3-4), certain of these new species do not fit into an
. Bulletin - United States National Museum. Science. New Cretaceous Index Foraminifera from Northern Alaska By Helen Tappan ' Introduction STUDY OF ROCK SAMPLES from Naval Petroleum Reserve No. 4, northern Alaska, over a period of about 8 years has shown that among the microfossils occurmg in the Cretaceous strata are several new species which because of their stratigraphic importance should be described. Possibly because the strata here considered are of a facies distinct from that of the better known Cretaceous horizons (Tappan, 1951, pp. 3-4), certain of these new species do not fit into any previously described genera and hence new genera are here described to include them. This paper describes 3 new genera and 34 new species, two-thirds of which are agglutinated forms. The calcareous species described are in large part Nodosariidae and rotaliform genera. Some reports that are in press or in preparation by other members of the U. S. Geological Survey describe the stratigraphy and structure of northern Alaska as deduced from field study and from information derived IU. S. Geological Survey and Research Associate, Smithsonian Institution. Pub- lication authorized by the Director, U. S. Geological Survey. by drilling in connection with the petroleum explor- ation in this region. Further information on the foraminiferal zonation in the surface and subsurface material, as well as foraminiferal range charts for the various wells, is presented in those reports. The Foraminifera discussed in this paper have been obtained from rocks ranging from Neocomian to Campanian in age. A correlation chart (text-fig. 29) shows how these Alaskan rocks are interrelated and how they fit into the European time scale. All type specimens of the species described in the presedt paper are deposited in the U. S. National Museima. Acknowledgments The writer is indebted to many of the geologists of the U. S. Geological Survey for collecting the samples from which these Foraminifera were obtai
Size: 2097px × 1191px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorun, bookcentury1800, bookdecade1870, booksubjectscience
