STRATIGRAPHIC ILLUMINATION: DIGITIZING THE USGS DENVER INOCERAMID COLLECTION

The USGS Denver fossil collection is the finest and most complete Upper Cretaceous Inoceramid collection (Cenomanian-Maastrichtian) in America or Europe. Alongside the similarly impressive ammonite collections, it provides the basis for fine-scale lithologic and chronologic analyses of the Upper Cretaceous US Western Interior research conducted by William A. Cobban. This collection is an important archiving component of the USGS Data Recovery Program.

We have thirty cases of Inoceramids that are sorted by genus and species within each stratigraphic stage. These fossil cases have seven to ten drawers. Each drawer has approximately 40 trays (varying number of specimens per tray). Specimens are generally small macrofossils between 1”-3” maximum length. Digital photographs were taken at and specimen label data recorded. Photographs were taken with in close-up view 300 dpi, an upper left light source displaying a standard lateral specimen view. Lighting and shadowing were adjusted to enhance the contrast of diagnostic morphologic characteristics. In addition, we introduced an innovative technique to whiten Inoceramids to enhance morphology. When numerous specimens of the same species were present, the best specimens were selected to photograph. Digital photos and taxonomic data will augment the USGS National Paleontologic Database as well as the USGS Denver Mesozoic database. The web version will associate photographs and lithologic section, visually illustrating the Cenomanian-Maastrichtian Inoceramids.