TR-J Cover.p65 - City of St. George

and having broader, shorter leaves rather than linear, needle-like leaves of
the latter. Milnerites planus differs from Saintgeorgeia jensenii by having
different shaped leaves that are closer together and not as curved and
by a flattened shoot.
Genus Podozamites (Brongniart) Braun in Munster, 1843
Discussion: Like Pagiophyllum, Podozamites is another in a series
of morphogenera based on leaf characters that are used for mainly
Mesozoic sterile coniferous foliage. Podozamites, as it is usually employed,
is distinguished from the others by having linear, lanceolate
leaves containing numerous parallel veins that converge apically. They
are borne alternately or spirally on long shoots.
Geologic range: Triassic throughout the Cretaceous.
cf. Podozamites
Figures 5A, 6C
Material: SGDS.558A.
Description and Discussion: Several small fragments of lamina
showing narrow parallel veins apparently represent Podozamites. The
size of the whole leaf is unknown, but the dimensions of the fragments
indicate that it was probably rather small. These fragments are comparable
to Podozamites distans (Presl) Braun and P. punctatus Harris from
the Rhaetic Scoresby Sound flora of East Greenland (Harris, 1935) (Fig.
5A). Although the lower part of the leaf shows elongate cells over the
veins, no other epidermal cells are visible.
SUMMARY
419
The flora from the SGDS is the first Early Jurassic flora reported
from western North America. The majority of Early Jurassic floras are
found in Eurasia. Early Jurassic floras are marked by an ascendance of
many Triassic types in Europe (Vakhrameev, 1991). Ferns were common,
as were conifers and bennettitalean forms, in many floras of this
age. Podozamites, Clathropteris, and Equisetum, present in the St. George
flora, were well represented in Early Jurassic floras in Eurasia. This flora
and fragments of other plant material which occur at the SGDS suggests
the flora was much more diverse when living and that more taxa will
likely be uncovered with additional collecting at other sites within and
adjacent to St. George.
ACKNOWLEDGMENTS
We are grateful to Andrew R.C. Milner (City Paleontologist, St.
George, Utah) who was responsible for collecting the material described
here and providing additional data, and to Dr. James I. Kirkland (State
Paleontologist, Utah Geological Survey) for inviting us to study this
flora. We acknowledge the assistance of Darcy Stewart, Paul Jensen and
the late Layton Ott for allowing collection of fossils on their properties,
Professor M.E. Popa (University of Bucharest) for reviewing the manuscript,
and to Dr. Brooks Britt (Department of Geology, Brigham Young
University) for his assistance with the illustrations.
REFERENCES
Ash, S.R., 1972, Plant megafossils of the Chinle Formation, in Breed, W.J.,
and Breed, C.S., eds., Investigations in the Triassic Chinle Formation:
Museum of Northern Arizona, Bulletin 47, p. 23-43.
Ash, S.R., 1980, Upper Triassic floral zones of North America, in Dilcher,
D.L. and Taylor, T.M., eds., Biostratigraphy of fossil plants: Stroudsburg,
Dowden, Hutchinson and Ross, Inc., p. 153-270.
Ash, S.R., 1999, An Upper Triassic upland flora from north-central New
Mexico, U.S.A.: Review of Palaeobotany and Palynology, v. 105, p.
183-199.
Ash, S.R., 2005, A new Upper Triassic flora and associated invertebrate
fossils from the basal beds of the Chinle Formation, near Cameron,
Arizona: PaleoBios, v. 25, p. 17-34.
Ash, S.R. and Tidwell, W.D., 1998. Plant megafossils from the Brushy Basin
Member of the Morrison Formation near Montezuma Creek Trading
Post, southeastern Utah, in Carpenter, K., Chure, D.J. and Kirkland, J.I.,
eds., The Upper Jurassic Morrison Formation: an interdisciplinary study,
part I: Modern Geology, v. 22, p.321-339.
Bock, W., 1954, Primaraucaria, a new araucarian genus from the Virginia
Triassic: Journal of Paleontology, v. 28, p. 32-42.
Bock, W., 1969, The American Triassic flora and global distribution: Research
Series, v. 3/4. North Wales, Geological Center, 406 p.
Brongniart, A., 1828, Prodrome d’une histoire des végétaux fossils: Paris,
F.G. Levrault, 223 p.
Brown, J.T., 1972. The flora of the Morrison Formation (Upper Jurassic)
of central Montana [Ph.D. dissertation]: Missoula, University of Montana,
65 p.
Calder, M.G., 1953, A coniferous petrified forest in Patagonia: Bulletin of
the British Museum (Natural History), Geology Series, v. 3, p. 99-138.
Carruthers, W., 1869, On some undescribed coniferous fruits from the secondary
rocks of Britain: Geological Magazine, v. 6, p. 1-7.
Cleal, C.J. and Rees, P.M., 2003, The Middle Jurassic flora from Stonesfield,
Oxfordshire, UK: Palaeontology, v. 46, p. 739-801.
Daugherty, L.H., 1941, The Upper Triassic flora of Arizona: Carnegie
Institution of Washington Contributions to Paleontology, v. 526, p. 1-
108.
Delevoryas, T. and Gould, R.E., 1971, An unusual fossil fructification from
the Jurassic of Oaxaca, Mexico: American Journal of Botany, v. 58, p.
616-620.
Delevoryas, T. and Gould, R.E., 1973, Investigations of North American
cycadeoids: williamsonian cones from the Jurassic of Oaxaca, Mexico:
Review of Palaeobotany and Palynology, v. 15, p. 27-42.
Fontaine, W.M., 1905a, The Jurassic flora of Douglas County, Oregon, in
Ward, L.F., Fontaine, W.M., Bibbins, A. and Wieland, G.R., eds., Status
of the Mesozoic floras of the United States: U.S. Geological Survey
Monograph, v. 48, p. 47-145.
Fontaine, W.M., 1905b, Flora of the Kootenai Formation, in Ward, L.F.
Fontaine, W.M., Bibbins, A. and Wieland, G.R., eds., Status of the Mesozoic
floras of the United States: U.S. Geological Survey Monograph, v.
48, p. 277-315.
Harris, T.M., 1926, The Rhaetic flora of Scoresby Sound, east Greenland:
Meddelelser om Grønland, v. 68, p. 1-147.
Harris, T.M., 1931, The fossil flora of Scoresby Sound, east Greenland, part
1, cryptogams (exclusive of Lycopodiales): Meddelelser om Grønland, v.
85, p. 1-102.
Harris, T.M., 1935, The fossil flora of Scoresby Sound, East Greenland,
part 4, Ginkgoales, Coniferales, Lycopodiales and isolated fructifications:
Meddelelser om Grønland, v. 112, p. 1-176.
Harris, T.M., 1961, The Yorkshire Jurassic flora. I: Thallophyta-
Pteridophyta: London, British Museum (Natural History), 221 p.
Harris, T.M., 1979, The Yorkshire Jurassic flora. V: Coniferales: London,
British Museum (Natural History), 166 p.
Heer, O., 1881, Contributions a la flora fossile du Portugal: Lisbon,
Comunicações dos Trabalhos do Serviços Geológicos de Portugal Lisbon
series 4, Section des Travaux Geologiques du Portugal, 51 p.
Hintze, L.F., 2005, Utah’s spectacular geology: how it came to be: Provo,
Department of Geology, Brigham Young University, 203 p.
Knobloch, E.A., 1972, Aachenia debeyi n. gen., n. sp. – eine neue Konifere
aus dem Senon von Aachen: Neues Jahrbuch für Geologie und Paläontologie
Monatshefte, v. 1972, p. 400-406.
Kirkland, J.I., Lockley, M.G. and Milner, A.R.C., 2002, The St. George
dinosaur tracksite: Utah Survey Notes, v. 34, p. 4-5, 12.