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1t =K taxa boundary. The position of this dinosaur was originally believed to be closer to the boundary (hence the name of the locality) because it was only about one meter below a lignite bed in the Fort Union Formation. However, palynologi-cal analysis revealed that this lignite bed is Maastrichtian in age. The K-T boundary was sought and located at the base of the superadjacent lignite bed, about two meters higher in the stratigraphic section (Figure 6.24). The significance of Figure 6.24 with respect to the Signor-Lipps effect is that an apparent trailing off in stratigraphically highest occurrences of K taxa can be seen in both the lower and upper series of samples. Note that only occurrences of angiosperm pollen are plotted in Figure 6.24 (most spores and gymnosperm pollen range through both sampled intervals and into the Paleocene). Clearly, the lower set of samples does not define an actual extinction horizon, yet the pattern of highest stratigraphic occurrences is the same as it is about two meters above, and the same as that seen at the other K-T boundary localities discussed here (compare Figures 6.15, 6.17, 6.21, 6.22, and 6.24). Similar patterns exist for the other 12 localities described by Nichols and Johnson (2002).

Figure 6.23 Photograph of the Terry's Fort Union Dinosaur section showing the position of the associated partial skeleton of a dinosaur (PTRM V96019) within Fort Union strata of Maastrichtian age (from Nichols and Johnson 2002). The Hell Creek-Fort Union contact is at the level of the pickax head, at the base of a lignite bed; the K-T boundary is near the top of the exposure. Pioneer Trails Regional Museum paleontologist Dean A. Pearson is kneeling by the plaster jacket containing the dinosaur bones. Reprinted by permission.

Figure 6.23 Photograph of the Terry's Fort Union Dinosaur section showing the position of the associated partial skeleton of a dinosaur (PTRM V96019) within Fort Union strata of Maastrichtian age (from Nichols and Johnson 2002). The Hell Creek-Fort Union contact is at the level of the pickax head, at the base of a lignite bed; the K-T boundary is near the top of the exposure. Pioneer Trails Regional Museum paleontologist Dean A. Pearson is kneeling by the plaster jacket containing the dinosaur bones. Reprinted by permission.

New Facet Boundary (locality 16; Figure 6.25), the last of the palynologically defined K-T boundary localities in the Marmarth area to be discussed here, provides important insights into the megafloral record across the boundary in the Williston Basin. At this locality, two lignite beds near the top of a mudstone interval bracket the K-T boundary, at the top of a 2-m-thick interval of Fort Union strata of Maastrichtian age. A distinctive and unusual Cretaceous mire megaflora is present in this interval, a "Fort Union zero'' (FU0) megaflora of Johnson (2002). It is more similar in composition to the typical Paleocene FUI megaflora than it is to the typical uppermost Maastrichtian HCIII megaflora of the region, but it is

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