In 1988, the presence of an Early Pennsylvanian ammonoid assemblage within the basal meter of the Callville Formation (Pennsylvanian-Permian), eastern Clark County, Nevada, was brought to the attention of the author by Stephen M. Rowland, University of Nevada-Las Vegas. The ammonoids occur in the Frenchman Mountain section described by Rowland (1987) for the Geological Society of America's Decade of North American Geology (DNAG) field trip compendium. The mid-Carboniferous section at this locality (Figure 1) was discussed in two other field trip guides as well (Langenheim and Webster, 1979; Webster et al., 1984). No ammonoids have been reported previously from this locality. Although this is the first record of Cancelloceras from the Great Basin region, the assemblage also provides a narrowly constrained age for the basal part of the Callville Formation at Frenchman Mountain, which in turn, dates the initiation of carbonate deposition following a major mid-Carboniferous hiatus in the southern Great Basin.
Serum Cytokine Variability During Simultaneous Radiation Chemotherapy in Patients With Malignancies in the Abdomen Basin Region Compared to Head and Neck Cancer and Healthy Volunteers