Summary
The Kayenta Formation is a geological formation in the Glen Canyon Group that is spread across the Colorado Plateau area of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah. Originally suggested as being Sinemurian-Pliensbachian, but more recent dating of detrital zircons has yielded a depositional age of 183.7 ± 2.7 Ma, thus a Pliensbachian-Toarcian age is more likely.[2] A previous depth work recovered a solid "Carixian" (Lower-Middle Pliensbachian) age from measurements done in the Tenney Canyon.[3] More recent works have provided varied datations for the layers, with samples from Colorado and Arizona suggesting 197.0±1.5-195.2±5.5 Ma (Middle Sinemurian), while the topmost section is likely Toarcian or close in age, maybe even recovering terrestrial deposits coeval with the Toarcian Oceanic Anoxic Event.[4] This last age asignation also correlated the Toarcian Vulcanism on the west Cordilleran Magmatic Arc, as the number of grains from this event correlate with the silt content in the sandstones of the upper layers.[4]
| Kayenta Formation | |
|---|---|
| Stratigraphic range: Sinemurian-Toarcian ~ | |
 Kayenta Formation, Capitol Reef National Park, Utah. | |
| Type | Geological formation |
| Unit of | Glen Canyon Group |
| Underlies | Navajo Sandstone |
| Overlies | Wingate Sandstone |
| Thickness | 100 to 120 metres (330 to 390 ft) |
| Lithology | |
| Primary | Sandstone |
| Other | Siltstone, Limestone |
| Location | |
| Coordinates | 37°48′N 110°36′W / 37.8°N 110.6°W |
| Country | United States |
| Extent | northern Arizona, northwest Colorado, Nevada, and Utah[1] |
| Type section | |
| Named for | Kayenta, Arizona |
This rock formation is particularly prominent in southeastern Utah, where it is seen in the main attractions of a number of national parks and monuments. These include Zion National Park, Capitol Reef National Park, the San Rafael Swell, and Canyonlands National Park.
The Kayenta Formation frequently appears as a thinner dark broken layer below Navajo Sandstone and above Wingate Sandstone (all three formations are in the same group). Together, these three formations can result in immense vertical cliffs of 600 metres (2,000 ft) or more. Kayenta layers are typically red to brown in color, forming broken ledges.
Kayenta Formation in Utah
editSoutheast Utah
edit
In most sections that include all three geologic formations of the Glen Canyon group the Kayenta is easily recognized. Even at a distance it appears as a dark-red, maroon, or lavender band of thin-bedded material between two thick, massive, cross bedded strata of buff, tan, or light-red color. Its position is also generally marked by a topographic break. Its weak beds form a bench or platform developed by stripping the Navajo sandstone back from the face of the Wingate cliffs. The Kayenta is made up of beds of sandstone, shale, and limestone, all lenticular, uneven at their tops, and discontinuous within short distances. They suggest deposits made by shifting streams of fluctuating volume. The sandstone beds, from less than 25 millimetres (1 in) to more than 3 metres (10 ft) thick, are composed of relatively coarse, well-rounded quartz grains cemented by lime and iron. The thicker beds are indefinitely cross bedded. The shales are essentially fine-grained, very thin sandstones that include lime concretions and balls of consolidated mud. The limestone appears as solid gray-blue beds, a few inches to a few feet thick, and as lenses of limestone conglomerate. Most of the limestone lenses are less than 8 metres (25 ft) long, but two were traced for nearly 150 metres (500 ft) and one for 500 metres (1,650 ft).
Viewed as a whole, the Kayenta is readily distinguished from the geologic formations above and below it. It is unlike them in composition, color, manner of bedding, and sedimentary history. Obviously the conditions of sedimentation changed in passing from the Wingate Sandstone formation to the Kayenta and from the Kayenta to the Navajo sandstone, but the nature and regional significance of the changes have not been determined. In some measured sections the transition from Wingate to Kayenta is gradual; the material in the basal Kayenta, beds seems to have been derived from the Wingate immediately below and redeposited with only the discordance characteristic of fluviatile sediments. But in many sections the contact between the two formations is unconformable; the basal Kayenta consists of conglomerate and lenticular sandstone that fills depressions eroded in the underlying beds. In Moqui Canyon near Red Cone Spring nearly 3 metres (10 ft) of Kayenta limestone conglomerate rests in a long meandering valley cut in Wingate. Likewise, the contact between the Kayenta and the Navajo in places seems to be gradational, but generally a thin jumbled mass of sandstone and shales, chunks of shale and limestone, mud balls, and concretions of lime and iron, lies at the base of the fine-grained, cross bedded Navajo. Mud cracks, a few ripple marks, and incipient drainage channels were observed in the topmost bed of the Kayenta on Red Rock Plateau; and in west Glen Canyon, wide sand-filled cracks appear at the horizon. These features indicate that, in places at least, the Wingate and Kayenta were exposed to erosion before their overlying geologic formations were deposited, are it may be that the range in thickness of the Kayenta thus in part (is) accounted for.
Southwest Utah
editThe red and mauve Kayenta siltstones and sandstones that form the slopes at base of the Navajo Sandstone cliffs record the record of low to moderate energy streams. Poole (1997) has shown that the streams still flowed toward the east depositing from 150 to 210 m (500 to 700 ft) of sediment here. The sedimentary structures showing the channel and flood plain deposits of streams are well exposed on switchbacks below the tunnel in Pine Creek Canyon.
In the southeastern part of Zion National Park a stratum of cross bedded sandstone is found roughly halfway between the top and bottom of the Kayenta Formation. It is a "tongue" of sandstone that merges with the Navajo formation east of Kanab, and it shows that desert conditions occurred briefly in this area during Kayenta time. This tongue is the ledge that shades the lower portion of the Emerald Pool Trail, and it is properly called Navajo, not Kayenta.
Fossil mudcracks attest to occasional seasonal climate, and thin limestones and fossilized trails of aquatic snails or worms mark the existence of ponds and lakes. The most interesting fossils, however, are the dinosaur tracks that are relatively common in Kayenta mudstone.
These vary in size, but all seem to be the tracks of three-toed reptiles that walked upright, leaving their tracks in the muds on the flood plains. Unfortunately, so far no bone materials have been found in Washington County that would enable more specific identification.
Apparently during Kayenta time Zion was situated in a climatic belt like that of Senegal with rainy summers and dry winters at the southern edge of a great desert. The influence of the desert was about to predominate, however, as North America drifted northward into the arid desert belt.
Glen Canyon
editThe Kayenta Formation is approximately 120 metres (400 ft) thick and consists of a fine-grained sandstone interbedded with layers of siltstone. The alternation of these units generally produces a series of ledges and slopes between the cliffs of the Navajo and Moenave formation. Dinosaur tracks are fairly common in the siltstone, and fresh water mussels and snails occur but are rare. The Kayenta Formation is colored pale red and adds to the splendor of the Vermilion Cliffs. It accumulated as deposits of rivers.
Fossils
editColor key
|
Notes Uncertain or tentative taxa are in small text; |
Invertebrates
edit| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
|
Base of the "typical facies" |
Valves |
A freshwater (lacustrine or fluvial) ostracod, type member of the family Darwinulidae. Kayenta specimens have a distinctive columnar calcitic layer. The Kayenta fauna is similar to the Sinemurian faunas of the Toutunhe Formation of Xinjiang, China. |
||
|
Liratina[5] |
|
|
Base of the "typical facies" |
Single shell |
A freshwater (lacustrine or fluvial) snail, incertae sedis inside Mesogastropoda. Differs considerably from the species from the Upper Jurassic Morrison Formation, Liratina jurassicum |
|
|
|
Base of the "typical facies" |
Shells |
A freshwater (lacustrine or fluvial) snail, member of the family Lymnaeidae. |
||
|
Scabriculocypris[5] |
S. n. sp |
|
Base of the "typical facies" |
Valves |
A freshwater (lacustrine or fluvial) ostracod, incertae sedis inside Cypridacea. Differs from all other described species of the genus in being more elongate and from most in being spinose. |
|
|
Unio[7] |
|
|
Base of the "typical facies" |
Shells |
A freshwater (lacustrine or fluvial) Bivalve, member of the family Unionidae. |
|
|
|
Base of the "typical facies" |
Shells |
A freshwater (lacustrine or fluvial) snail, member of the family Valvatidae. |
Fishes
editThe "Kayenta Fish Fauna" is the last one recovered from the Glen Canyon Group sequence and it is delimited mostly to the silty facies of the Lower-Middle Part of the formation.[8] This Fauna is rather scarce and delimited to several concrete locations with proper lacustrine or fluvial deposition, and are also scarce due to preservation bias.[8] Another aspect that can explain the lack of fish fossils found is the use of different research techniques than used on the Chinle Formation.[8]
Chondrichthyes
edit| Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
Indeterminate |
|
Base of the "typical facies" |
UCMP 136104, 136105 + ten uncatalogued specimens, teeth |
A freshwater (lacustrine or fluvial) non-neoselachian shark, incertae sedis inside Hybodontoidea. The remains of sharks are rather rare on the formation and limited to several locations with typical lacustrine or fluvial floodplain deposition. |
||
|
Toarcibatidae (= "Archaeobatidae")[10] |
Indeterminate |
Gold Spring Quarry 1 |
Base of the "typical facies" |
Isolated Tooth |
A freshwater (lacustrine or fluvial) toarcibatid. Related originally with Micropristis or Libanopristis, and stated to be reworked from younger Cretaceous deposits, was found due to its asymmetrical cusp to fit within the definition of Toarcibatis, being more likely to be native of the formation.[10] |
Actinopterygii
edit| Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
Lophionotus[11] |
L. kanabensis |
|
Base of the "typical facies" |
|
A freshwater (lacustrine or fluvial) semionotid semionotiform. |
|
|
Indeterminate |
|
Base of the "typical facies" |
|
A freshwater (lacustrine or fluvial) palaeoniscid palaeonisciform. |
||
|
Indeterminate |
|
Base of the "typical facies" |
|
A freshwater (lacustrine or fluvial) semionotid semionotiform, probably related to the genus Semionotus. Semionotiformes are the only properly identified bony fishes from the formation, including a large specimen exposed at the Dan O’Laurie Museum.[8] |
 |
Sarcopterygii
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
C. stewarti |
|
Middle “Silty Facies” |
|
A freshwater (lacustrine or fluvial) ceratodontid dipnomorph (lungfish). |
 | |
|
Indeterminate |
|
Base of the "typical facies" |
|
A freshwater (lacustrine or fluvial) coelacanthid Coelacanthiform. Coelacanths are quoted from this zone, but their remains have not been studied. |
||
|
P. guentheri |
|
Middle “Silty Facies” |
|
A freshwater (lacustrine or fluvial) ceratodontid dipnomorph (lungfish). Was described as C. felchi, know from the Upper Jurassic Morrison Formation. Other dipnoan specimens have been cited but never described.[14] |
Amphibia
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
Indeterminate |
Gold Spring Quarry 1 |
Silty Facies Member |
|
An early frog, incertae sedis relationships |
||
|
E. micropodia |
Gold Spring Quarry 1 |
Silty Facies Member |
|
A genus whose relationships are controversial, being considered one of the earliest gymnophionans as a close relative of caecilians |
 | |
| Indeterminate |
Gold Spring Quarry 1 |
Silty Facies Member |
|
Incertae sedis relationships |
||
|
P. bitis |
Gold Spring Quarry 1 |
Silty Facies Member |
MNA V 8725, associated desarticulated remains of 2 individuals; referred MCZ 9324 A & MCZ 9323 A |
An early frog, probably related to Notobatrachidae |
 | |
|
Indeterminate |
Gold Spring Quarry 1 |
Silty Facies Member |
MCZ 9017, 9018, atlas vertebrae |
A possible stem-salamander, incertae sedis inside Urodela. The oldest record of an urodelan from North America |
Reptilia
editRhynchocephalia
edit| Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
N. sani |
|
Silty Facies |
|
An Advanced Sphenodont, member of Sphenodontinae. The skeleton of N. sani shows a large number of similarities with the modern tuatara S. punctatus, clustering them closely together in the morphospace of sphenodontians and early lepidosaurs.[18] |
 | |
|
Indeterminate |
Airhead West |
Silty Facies |
Uncertain Fragments |
Rhynchocephalians of uncertain assignment |
||
|
Indeterminate |
Gold Spring Quarry 1 |
Silty Facies |
MCZ 9036 through 9040, jaw fragments |
An indeterminate sphenodont |
Testudinatans
edit| Genus / taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
Indeterminate |
Red Knob |
Silty Facies |
Uncertain fragments |
Cryptodirans of uncertain assignment |
||
|
|
Silty Facies Member |
|
 | ||
|
Indeterminate |
|
Silty Facies |
Uncertain fragments |
Testudinatans of uncertain assignment |
Crocodylomorphs
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
C. valliceps |
Adeii Eechii Cliffs, Navajo Nation |
Silty Facies |
TMM 43631-1 (holotype), partial skull |
A terrestrial member of the Hsisosuchidae. Alternatively can be a relative of Thalattosuchia |
||
|
|
Silty Facies |
|
Indeterminate crocodylomorphs. Includes a new taxon with skull similar to Orthosuchus stormbergi. |
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|
E. colberti |
Blue layer, Silty Facies |
Silty Facies |
|
An early terrestrial or semiterrestrial protosuchid crocodylomorph |
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|
K. walkeri |
|
Silty Facies |
|
An early terrestrial or semiterrestrial crocodylomorph |
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|
|
Silty Facies |
|
Early terrestrial or semi-terrestrial herbivorous Crocodylomorphs. Includes two taxa similar to the Cretaceous Edentosuchus tienshanensis, one that has been referred to informally as "Gomphosuchus" (including UCMP 97638 and UCMP 125871) and another unnamed taxon (including UCMP 130082).[25] Previously considered one taxon (the 'Kayenta form') in older literature.[26] |
Dinosaurs
editIndeterminate ornithischian remains located in Arizona, USA.[27] Ornithischian tracks located in Arizona, USA.[27] Indeterminate theropod remains located in Arizona, US.[27] Theropod tracks located in Arizona and Utah, US.[27] Possible theropod tracks located in Arizona, Colorado, and Utah, US.[27]
Ornithischians
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
Indeterminate |
Gold Springs |
Silty Facies |
|
A heterodontosaurid of uncertain placement. Appears to have been an insectivore downsized to a degree not seen before among early dinosaurs. |
||
|
|
Silty Facies |
|
A uncertain placement large ornithischian and teeth from diverse type of genera. The femur was assigned to Dilophosaurus wetherilli.[30] The femur resembles that of the early neornithischian Lesothosaurus.[31] |
||
|
S. sp. (S. "arizonensis") |
Valley of the Buttes |
Silty Facies |
UCMP 130056, scutes |
A controversial thyreophoran, resembles the osteoderms of S. harrisonii. |
||
|
S. lawleri |
|
Silty Facies |
|
A basal thyreophoran, the most abundant dinosaur of the formation |
 |
Sauropodomorphs
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
S. aurifontanalis[27] |
|
Silty Facies |
|
A sauropodomorph, a member of the family Massospondylidae. Originally thought to be Massospondylus[27] |
 |
Theropods
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
Unnamed, informally known as the "Shake-N-Bake" coelophysid |
|
Silty Facies |
|
A coelophysid neotheropod. |
||
|
Silty Facies |
|
A coelophysid neotheropod. Referred to as Syntarsus by Weishampel et al.[27] Formerly known as Megapnosaurus. |
 | ||
| D. wetherilli |
|
Silty Facies |
|
An advanced neotheropod, type member of the family Dilophosauridae. Dilophosaurus is the main identified dinosaur from the formation, being both the most known and studied. It was among the largest theropods present locally, and very likely an active hunter, rather than a fisher.[42] |
 | |
|
K. elysiae[43] |
Willow Springs |
Silty Facies |
|
A neotheropod of uncertain relationships, probably a coelophysoid. Originally referred to M. kayentakatae by Rowe. |
 | |
|
Indeterminate |
|
Silty Facies |
|
Incertae sedis within Theropoda, probably Neotheropoda |
Pterosauria
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
Indeterminate |
|
Silty Facies |
|
Possible pterosaur teeth |
||
|
R. jenkinsi[45] |
|
Silty Facies, Ward Mesa |
|
A pterosaur, considered a member of the family Dimorphodontidae. Was originally classified as a "rhamphorhynchoid", represents the only major pterosaur identified from the formation and one of the oldest from North America. |
Synapsida
edit| Genus / Taxon | Species | Location | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|---|
|
|
Silty Facies |
|
A relatively large and common tritylodont |
||
|
D. nezorum |
|
Silty Facies |
|
A mammaliaform, member of the family Megazostrodontidae |
||
|
Indeterminate |
|
Silty Facies |
|
Incertae sedis, a possible haramiyid |
||
|
|
Silty Facies |
|
A Large tritylodont, with a suggested semiaquatic mode of life. A specimen has been recovered with several associated perinates.[49] |
 | |
|
M. sp. |
|
Silty Facies |
|
A mammaliaform, member of the family Morganucodontidae |
 | |
|
|
Silty Facies |
|
A tritylodont, also present on coeval deposits from Asia and Europe. |
 | |
|
Indeterminate |
|
Silty Facies |
|
Indeterminate tritylodontid remains |
Ichnofossils
edit| Genus | Species | Location | Material | Type | Origin | Notes | Images |
|---|---|---|---|---|---|---|---|
|
|
Footprints |
Moving Tracks |
|
Ornithischian Footprints of the ichnofamily Moyenisauropodidae. |
||
|
|
Tracks |
Moving Tracks |
|
Pseudosuchia Footprints of the ichnofamily Batrachopodidae. |
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|
|
Tracks |
Moving Trails |
|
Dinosaur Traces left while swimming |
||
|
|
Footprints |
Moving Tracks |
|
Theropod Footprints of the ichnofamily Grallatoridae. |
||
| Indeterminate |
|
Footprints |
Moving Tracks |
|
Possible Dinosaur Footprints, non assigned to any concrete ichnogenus |
 | |
|
|
Footprints |
Moving Tracks |
|
Theropod Footprints of the ichnofamily Grallatoridae. This type of tracks match with Dilophosaurus pes |
||
|
|
Footprints |
Moving Tracks |
|
Theropod Footprints of the ichnofamily Grallatoridae. Likely from smaller local theropods |
||
|
|
Footprints |
Moving Tracks |
|
Theropod Footprints of the ichnofamily Grallatoridae. |
||
| Indeterminate |
|
Trackways |
Moving Tracks |
|
Saltwater/Blackish-linked tracks with resemblance with extant Xiphosuran traces |
||
|
|
Footprints |
Moving Tracks |
|
Ornithischian Footprints of the ichnofamily Moyenisauropodidae. |
||
|
|
Footprints |
Moving Tracks |
|
Theropod Footprints of the ichnofamily Otozoidae. Includes tracks referable to bipedal Sauropodomorphs |
||
|
|
Cylindrical burrows |
Pascichnia |
|
Burrow-like ichnofossils. It is referred to vermiform deposit-feeders. It is controversial, since is considered a strictly a junior synonym of Palaeophycus.[65] |
 | |
|
|
Cylindrical to subcylindrical Burrows |
Domichnia |
|
Burrow-like ichnofossils. Ichnofossils done by organisms advancing along the bottom surface. Very narrow, vertical or subvertical, slightly winding unlined shafts filled with mud. Interpreted as dwelling structures of vermiform animals, more concretely the Domichnion of a suspension-feeding Worm or Phoronidan, with certain Skolithos representing entrance shafts to more complicated burrows. |
 | |
|
Synapsidipedia[51] |
Indeterminate |
|
Tracks |
Moving Tracks |
|
Possible Synapsid Footprints, non assigned to any concrete ichnogenus |
|
|
|
Unlined meniscate burrows |
Fodinichnia |
|
Saltwater/Blackish burrow-like ichnofossils. Taenidium is a meniscate backfill structure, usually considered to be produced by an animal progressing axially through the sediment and depositing alternating packets of differently constituted sediment behind it as it moves forward. |
||
| Indeterminate |
|
Footprints |
Moving Tracks |
|
Possible Theropod Footprints, non assigned to any concrete ichnogenus |
 | |
|
|
Trails |
Moving Trails |
|
Fish-swimming fossil trail left as a fossil impression on a substrate |
Plants
edit| Genus | Species | Stratigraphic position | Material | Notes | Images |
|---|---|---|---|---|---|
|
Clathropteris[13] |
|
|
|
Affinities with Dipteridaceae inside Polypodiales. |
 |
| Indeterminate |
|
|
Affinities with Cycadidae inside Cycadopsida. |
 | |
|
|
|
Affinities with Williamsoniaceae inside Bennettitales. |
||
| Indeterminate |
|
|
|||
|
|
|
A member of Williamsoniaceae inside Bennettitales. It has been interpreted as a cycad in the family Cycadaceae or a Bennettitalean plant, and also a late surviving member of Noeggerathiales. |
 |
See also
edit- Kayenta, Arizona
- List of dinosaur-bearing rock formations
- List of fossil sites (with link directory)
Footnotes
edit- ^ Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Jurassic, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. pp. 530–532. ISBN 0-520-24209-2.
- ^ Marsh, A.D.; Rowe, T.; Simonetti, A.; Stockli, D.; Stockli, L. (2014). "The age of the Kayenta Formation of northeastern Arizona: overcoming the challenges of dating fossil bone". J. Vertebr. Paleontol. Prog. Abst. 34 (2): 178. Retrieved 19 November 2021.
- ^ Steiner, M.; Tanner, L.H. (2014). "Magnetostratigraphy and paleopoles of the Kayenta Formation and the Tenney Canyon Tongue" (PDF). Volumina Jurassica. 12: 31–38. Retrieved 7 March 2022.
- ^ a b Marsh, Adam Douglas (2018). "Contextualizing the evolution of theropod dinosaurs in western North America using U-Pb geochronology of the Chinle Formation and Kayenta Formation on the Colorado Plateau". UT Electronic Theses and Dissertations. doi:10.26153/tsw/41876.
- ^ a b c Kietzke, K.K.; Lucas, S.G. (1995). "Ostracoda and Gastropoda from the Kayenta Formation (Lower Jurassic) of Arizona, U.S.A". Journal of Arizona–Nevada Academy of Science. 28 (1–2): 23–32. JSTOR 40024298. Retrieved 19 November 2021.
- ^ a b Lewis, G. E.; Irwin, J. H.; Wilson, R. F. (1961). "Age of the Glen Canyon Group (Triassic and Jurassic) on the Colorado Plateau". Geological Society of America Bulletin. 72 (9): 1437–1440. Bibcode:1961GSAB...72.1437L. doi:10.1130/0016-7606(1961)72[1437:AOTGCG]2.0.CO;2. Retrieved 2 January 2022.
- ^ Harshbarger, J.W.; Repenning, C.A.; Irwin, J.H. (1957). "Stratigraphy of the uppermost Triassic and the Jurassic rocks of the Navajo Country" (PDF). United States Geological Survey Professional Paper. 291 (1): 1–74. Retrieved 2 January 2022.
- ^ a b c d e f g Milner, A. R.; Kirkland, J. I.; Birthisel, T. A. (2006). "The geographic distribution and biostratigraphy of Late Triassic–Early Jurassic freshwater fish faunas of the southwestern United States". New Mexico Museum of Natural History and Science Bulletin. 37 (1): 522–529. Retrieved 19 November 2021.
- ^ a b c d e f g h i j Curtis, K.; Padian, K. (1999). "An Early Jurassic microvertebrate fauna from the Kayenta Formation of northeastern Arizona: microfaunal change across the Triassic-Jurassic boundary". PaleoBios. 19 (1): 19–37.
- ^ a b Delsate, D.; Candoni, L. (2001). "Description de nouveaux morphotypes dentaires de Batomorphii toarciens (Jurassique inférieur) du Bassin de Paris: Archaeobatidae nov. fam". Bulletin-Société des Naturalistes Luxembourgeois. 102 (1): 131–143. Retrieved 19 November 2021.
- ^ a b Milner, A. R. C.; Birthisel, T. A.; Kirkland, J. I.; Breithaupt, B.H; Matthews, N. A.; Lockley, M. G.; Santucci, V. L.; Gibson, S. Z; DeBlieux, D. D.; Hurlbut, M.; Harris, J. D.; Olsen, P. E. (2011). "Tracking Early jurassic dinosaurs across southwestern Utah and the Triassic-Jurassic transition". Nevada State Museum Paleontological Papers. 1 (1): 1–107.
- ^ a b c d Gay, R. J.; Milner, A. R. (2015). "The first report of an archosaur from the Kayenta Formation of Washington County, Utah" (PDF). PeerJ PrePrints. 1048 (1): 1–21. Retrieved 19 November 2021.
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References
edit- Geology of Eastern Iron County, Utah by Herbert E. Gregory Utah Geological and Mineral Survey Bulletin No. 37 (1950)
- The San Juan Country – A Geographic and Reconnaissance of Southeastern Utah by Herbert E. Gregory. U.S. Geological Survey Professional Paper No. 188
- Geology Studies, Vol. 15 Part 5 (1968)
- Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2.
External links
edit- U.S.G.S Lexicon of Colorado Plateau Stratigraphy