The Upper Cretaceous (Campanian) ammonite and inoceramid bivalve succession at Sand Creek, Colusa County, California, and its implications for establishment of an Upper Cretaceous Great Valley Sequence ammonite zonation abb: 2
Ward, Peter D.; Haggart, James
Newsletters on Stratigraphy Volume 10 Number 3 (1981), p. 140 - 147
published: Dec 18, 1981
ArtNo. ESP026001003006, Price: 29.00 €
Megafossil collections from strata of Campanian age on Sand Creek, Colusa County, California show the presence of three stratigraphically differentiable ammonite and inoceramid faunules. In ascending order, these three faunules are correlative with the Inoceramus schmidti Zone, Baculites chicoensis Zone, and Hoplitoplacenticeras vancouverense Zone of the Nanaimo Group (Ward, 1978a). The Sand Creek locality is the only known area in California where these three megafossil assemblages can be recognized in the same section. The succession of species on Sand Creek indicates that previous reports on the relative stratigraphic distribution of Campanian index ammonites and inoceramids in California are incorrect.