Study of the Early Cretaceous (Albian) Faunas of the Cottonwood District

该项目将建立一个现代生物地层学基础，用于研究北美环太平洋地区中白垩纪（阿尔bian）动物群（主要是菊石）的生物地层学、生物地理学和演化，并将完善加州北部棉桐区这一时期的生物地层学参考标准。详细的参考标准是理解生物相、生物地理学和演化模式的古生物问题以及年代地层学的先决条件。需要高度生物地层学分辨率的地层学和构造问题也需要它。这样的研究将：1)阐明许多未被研究过的菊石类群的显微结构、形态和个体发生特征；2)将使某些进化序列得以识别并对其模式进行检验；3)允许对德国、俄罗斯和法国作家提出的菊石进化假说进行检验；4)使环太平洋地区的下白垩纪地层与欧洲的经典剖面以及起源于特提斯海道（如高加索、印度）的层序得以精确对比；5)使古地理和生物表面解释成为可能，其中一些解释现在被过时的分类所掩盖；6)更好地了解该地区及其动物的历史；7)允许对北美白垩纪历史有一个更平衡的看法；8)允许对提出的白垩纪中期灭绝事件进行评估。

The project will establish a modern taxonomic base for studies of biostratigraphy, biogeography, and evolution of the middle Cretaceous (Albian) faunas (predominantly ammonites) of the Pacific rim of North America and will refine the biostratigraphic standard of reference for this interval in the Cottonwood District of northern California. A detailed standard of reference is prerequisite to an understanding of paleobiological problems of biofacies, biogeography and patterns of evolution, and for chronostratigraphy. It is also needed for stratigraphic and structural problems requiring a high degree of biostratigraphic resolution. Such a study would: 1) elucidate the microstructural, morphologic, and ontogenetic characteristics of many unstudied ammonite taxa; 2) would enable some evolutionary sequences to be recognized and their patterns to be examined; 3) permit examination of hypotheses of ammonite evolution proposed by German, Russian, and French writers; 4) enable a refined correlation of the Lower Cretaceous strata around the Pacific rim with the classical sections in Europe and with sequences originating in the Tethyan seaway, e.g. Caucasus, Indian; 5) enable paleobiogeographic and biofacial interpretations some of which are now masked by antiquated taxonomy; 6) permit a better understanding of the history of the region and its faunas; 7) permit a more balanced view of the Cretaceous history of North America; 8) permit assessment of proposed mid-Cretaceous extinction events.