PALEOECOLOGY OF THE UPPER HELL CREEK FORMATION ASCERTAINED FROM FLORA ASSOCIATED WITH A TRICERATOPS SITE NEAR MARMARTH, NORTH DAKOTA

The Hell Creek formation in southwestern North Dakota has a vast array of fossils from a variety of different plants and animals. This paper discusses some plant fossils, in the form of seeds and leaves, found near Marmarth, ND in a Triceratops fossil site, only a few meters below the Cretaceous/Tertiary boundary. Our goal is to determine more details of the paleoenvironment. X-ray diffraction tests show that the matrices are almost entirely quartz sandstone, with a notable amount of hematite. The seed fossils were thin sectioned and determined to be dicotyledonous, though were indistinguishable beyond this identification. The leaf fossils were determined to be of the Dryophyllum genus. These terrestrial fossils are consistent with the Triceratops fossils found in the same area. However, the hematite content in the matrices indicates there was most likely water in this area. These findings are congruent with other studies of the Hell Creek formation which find that this region was a series of rivers and deltas during the Maastrichtian Age. More fossil samples could lend to a better paleoecological manifestation of this area.