The axial column in Labidosaurus is thoroughly described. Two different vertebral “morphs” are found to occur in this genus. One type is that which is classically illustrated for Labidosaurus, while the other shows alternation in height and construction of the neural arches and neural spines. A brief description of the modifications of muscle attachments in alternating forms is outlined. Analysis shows that such a structural modification probably allowed (more) efficient dorsiflexion and lateral flexion of the vertebral column. The occurrence of alternation of neural spine and arch structure is probably a primitive characteristic, but becomes variously modified in different forms. The variability observed in the axial column suggests that Labidosaurus may have been sexually dimorphic, or that the genus may consist of two different species.

A sinkhole locality in the Wasatch Plateau has yielded Utah's first record of the American mastodon. At nearly 3,000 m this fossil-bearing site denotes the highest elevation yet reported for Mammut americanum, and demonstrates that mountainous terrain was not a barrier to dispersals. A presumably preferred habitat of spruce-fir open forests, similar to that in the area today, was present during the time of the mastodons reported here. Two incomplete individuals of M. americanum are the only fossils that were found in the sinkhole. Entrapment appears to have been the cause of death. Since the record of M. americanum in western North America is sparse, the present find has added significance in providing more information about the nature of this animal. A possible association of a recovered spear point fragment near the fossils indicates the possibility that man and mastodon were contemporaneous here. Three independent datings were run on mastodon bone. Two based on carbon-14 yielded dates of 7,090 ± 200 yr B.P. and 7,590 ± 100 yr B.P., while the third, using the racemization process, indicated an age of less than 10,000 yr B.P.

Dictyastrum chestriensis n. gen. and sp. is a seed fern that occurs in the Chester Series (Upper Mississippian) of the Illinois Basin, and is based on compressions, impressions, and pyritemarcasite petrifactions of the stem and frond. The stem has a mixed prostele with indistinct protoxylem, and the larger specimens have a thin zone of secondary xylem that contains many small rays. The inner cortex contains numerous transversely-oriented sclerotic nests, whereas the outer cortex contains prominent anastomosing fiber bundles that produce the Dictyoxylon-type pattern that is frequently observable on compressions and impressions. The petiole is massive, has an expanded base, and forks distally into unequal subdivisions. The distal frond has small pinnules with rounded lobes and corresponds to the form species Sphenopteris stricta (=S. bermudensiformis), which is used for isolated compressions and impressions. Dictyastrum chestriensis belongs to the Lyginopteridales and is intermediate morphologically between Lyginopteris and Heterangium.

The description of Norian conodonts from northwest Nevada recently published (Meek, 1984) includes reference to a new Late Triassic conodont Epigondolella humboldtensis n. sp. on p. 316, fig. 2 and PL 1, figs. 5-11 and 19. Description of this species was to have been included as appendix 3 to the paper but was inadvertently omitted. In order to conform to the international rules of zoological nomenclature, a description of the species follows and this becomes the valid reference for Epigondolella humboldtensis n. sp.

Hadrosaur Bones have been found on the Colville River north of Umiat on the North Slope of Alaska. This find represents the first report of dinosaur bones in Alaska and their northernmost reported occurrence. The remains are not determinable below family level but are important, nonetheless, for interpretations of the paleoclimatology and paleobiogeography of the Late Cretaceous.