A state is not a point, and this one is Vernal, in the north-east corner. Of the 218 fossils in its box, 210 are recorded as living on land — this is dinosaur country, not sea floor. The row worth stopping at is 66 million years ago, where the rock around here says two things at once and no fossil is close enough to settle it. This page reports that and does not resolve it. Picking the louder half would be inventing a result, and an argument in the evidence is a fact about the evidence.
Five ages in the past of this place, each one a window rather than a day. Each says which witness spoke — and where our evidence cannot answer yet, it says that too.
“Ma” means millions of years ago. The dashed mark means our sources have nothing for that age — which is a finding, not a fault.
The age where the rock contradicts itself
66 million years ago
The rock units the database holds for this region at this age do not agree with each other: some record a sea, some record dry land. And no fossil near this town is grouped with this age, so there is nothing local to break the tie.
This is the thinnest ground this site stands on anywhere. One kind of evidence, arguing with itself, with nothing to check it against.
What this page does about it is nothing, deliberately. It does not count which side has more rock units behind it: this site does not treat records as votes, and that mechanism existed once and was taken out. It does not say which is more likely; nothing here measures likelihood. It says the evidence disagrees, and leaves the disagreement where it found it.
The rest of the page is steadier and points a different way: 210 of the 218 fossils in this box are recorded as living on land. Whatever was happening at that one contradictory age, most of what has been dug up around here did not live in the sea.
Travel back in time
One of these rows contains a disagreement rather than an answer. It is printed the same size as the others, being just as much of a result.
250
million years agojump to the evidence250 million years ago, the plate model puts this ground almost on the equator. This is one of the ages the models argue about most: published reconstructions put it as much as 5° of latitude apart, which is several hundred kilometres. Treat it as one model's answer, not a photograph.
200
million years agojump to the evidence200 million years ago, the plate model puts this ground about 18° north of the equator. Published models agree more closely here, within about 2.5° of latitude, but it is still one model's answer rather than a photograph.
150
million years agojump to the evidence150 million years ago, the plate model puts this ground about 27° north of the equator. Published models disagree by about 4.3° of latitude here — a few hundred kilometres — so it is one model's answer, not a photograph.
100
million years agojump to the evidence100 million years ago, the plate model puts this ground about 39° north of the equator. Published models disagree by about 3.1° of latitude here — a few hundred kilometres — so it is one model's answer, not a photograph.
66
million years agojump to the evidence66 million years ago, the plate model puts this ground about 45° north of the equator. Published models agree more closely here, within about 1° of latitude, but it is still one model's answer rather than a photograph.
What was the water doing?
Five ages, oldest first. Each one has two kinds of witness — the rock of the wider region, and the fossils dug up near the town — and they are kept apart on purpose, because they are answers to different questions.
Each age here is a marker on the timeline, not a single day. The evidence that belongs to it comes with an age range of its own that overlaps the marker — so it can tell you what this stretch of time was like, and never what was happening on one exact date.
The rock of the region says sea
Around 250 million years ago
250 million years ago, the plate model puts this ground almost on the equator. This is one of the ages the models argue about most: published reconstructions put it as much as 5° of latitude apart, which is several hundred kilometres. Treat it as one model's answer, not a photograph.
The rock of the region
Across the wider region, the rock from 250 million years ago — the Moenkopi Fm — was laid down in the sea. That is a statement about roughly 22,200 square kilometres of region, centred about 41 km from the town — not about the ground under one street.
The fossils dug up nearby
No fossil dug up near here has an age range that covers 250 million years ago, so there is no local evidence for this exact age.
The rock of the region says land
Around 200 million years ago
200 million years ago, the plate model puts this ground about 18° north of the equator. Published models agree more closely here, within about 2.5° of latitude, but it is still one model's answer rather than a photograph.
The rock of the region
Across the wider region, the rock from 200 million years ago — the Nugget Sandstone — was laid down on land, not under the sea. That is a statement about roughly 22,200 square kilometres of region, centred about 41 km from the town — not about the ground under one street.
The fossils dug up nearby
13 fossils dug up near Vernal have an age range covering 200 million years ago: 0 from the sea, 13 from land. The closest of them was found about 25 km away — near the town, never under it.
The rock of the region says land
Around 150 million years ago
150 million years ago, the plate model puts this ground about 27° north of the equator. Published models disagree by about 4.3° of latitude here — a few hundred kilometres — so it is one model's answer, not a photograph.
The rock of the region
Across the wider region, the rock from 150 million years ago — the Morrison Fm — was laid down on land, not under the sea. That is a statement about roughly 22,200 square kilometres of region, centred about 41 km from the town — not about the ground under one street.
The fossils dug up nearby
36 fossils dug up near Vernal have an age range covering 150 million years ago: 0 from the sea, 36 from land. The closest of them was found about 0.4 km away — near the town, never under it.
Only the fossils speak
Around 100 million years ago
100 million years ago, the plate model puts this ground about 39° north of the equator. Published models disagree by about 3.1° of latitude here — a few hundred kilometres — so it is one model's answer, not a photograph.
The rock of the region
No rock layer from 100 million years ago survives in the regional record here, so the rock has nothing to say about this age.
The fossils dug up nearby
3 fossils dug up near Vernal have an age range covering 100 million years ago: 1 from the sea, 2 from land. The closest of them was found about 13 km away — near the town, never under it.
One formation, both worlds
Around 66 million years ago
66 million years ago, the plate model puts this ground about 45° north of the equator. Published models agree more closely here, within about 1° of latitude, but it is still one model's answer rather than a photograph.
The rock of the region
Across the wider region, the rock from 66 million years ago carries both kinds of environment — parts of it laid down in the sea, parts of it on land. That is a statement about roughly 22,200 square kilometres of region, centred about 41 km from the town — not about the ground under one street.
The fossils dug up nearby
No fossil dug up near here has an age range that covers 66 million years ago, so there is no local evidence for this exact age.
What was dug up nearby?
All dug up around Vernal, none from beneath it, so each row carries the distance to its dig. This is a land-animal record almost throughout, which is unusual on a site with "underwater" in its addresses.
Around 66 million years ago
A Thescelus insiliens from around this time (its own age range is 72.2–83.6 million years) was dug up about 23 km from here, in the Mesaverde.
Around 100 million years ago
A Dromaeosauridae from around this time (its own age range is 100.5–143.1 million years) was dug up about 7.0 km from here, in the Cedar Mountain, Uintah County.
A fossil the database can only call “Ankylosauria” from around this time (its own age range is 100.5–143.1 million years) was dug up about 7.0 km from here, in the Cedar Mountain, Uintah County.
A trace fossil called Koreanaornis hamanensis — a name for a mark an animal left, not for the animal itself — from 100 million years ago was dug up about 13 km from here, in the Naturita, Uintah County.
Around 150 million years ago
A Stegosaurus from 150 million years ago was dug up about 0.4 km from here, in the Morrison, Uintah County.
An Allosaurus from 150 million years ago was dug up about 0.4 km from here, in the Morrison (Salt Wash), Uintah County.
A Dryosaurus from 150 million years ago was dug up about 0.4 km from here, in the Morrison (Salt Wash), Uintah County.
Around 200 million years ago
A fossil the database can only call “Dinosauria” from around this time (its own age range is 201.4–205.7 million years) was dug up about 13 km from here, in the Navajo-Nugget Sandstone, Uintah County.
A fossil the database can only call “Dinosauria” from around this time (its own age range is 201.4–227.3 million years) was dug up about 13 km from here, in the Popo Agie, Uintah County.
A fossil the database can only call “Dinosauria” from around this time (its own age range is 201.4–227.3 million years) was dug up about 14 km from here, in the Popo Agie, Uintah County.
We show these places to the nearest few kilometres rather than pinning them exactly. The scientists who recorded them know the spot far better than that — the full record is one click away in the Paleobiology Database, and it is free for anyone to read. We round them here because a map made for children is not a map for digging things up, not because anything is being hidden.
What changed?
The model places this ground at all five ages and moves it north as the page comes forward. That is a statement about position and not about what covered it.
The rock at the surface today is younger than all of it. The geological map of this exact point returns Mesozoic sedimentary rocks (Mesozoic), Late Cretaceous sedimentary (Late Cretaceous), Older alluvial deposits (Cenozoic), mixed alluvium and eolian deposits (Holocene).
Utah is more than 500 km across and the state capital's own box STOPs this site's science gate at four of five ages. This page is one corner of it and says so.
Try it yourself
The animals here drank fresh water in a place that is now high desert. The water did not disappear when they did.
A good page for what to do when your sources disagree. The answer is not to average them or to pick the loudest — it is to say they disagree and to be clear that you have not settled it.
If two pieces of evidence say opposite things and you cannot test either, what is the honest thing to write down?
How sure are we?
Column facts describe an area of thousands to tens of thousands of km², centred tens of kilometres from the town coordinate. They are claims about a region, never about the rock beneath the town.
Fossil facts are a bounding-box sample around the town, each with its own distance from it; a fossil is never "here". The absence of fossils is not evidence of the absence of life — only of the absence of a recorded, published dig in this box.
Positions are model outputs, not observations. Independent plate models disagree by hundreds of kilometres at these ages, and that spread is the honest size of the uncertainty.
The land/sea question is answered only by the regional rock and the local fossils, separately, and never by the reconstruction — which says where this ground was and cannot say whether it was wet. There is deliberately no single field holding a one-word answer, because answering in one word would require merging a regional claim with a local one (CLAUDE.md rule 5). The nearby fossils are reported as a census of what has been found — which kinds are present, and how many of each — and never counted into a verdict: occurrence records are not statistically equivalent observations, so a plurality of them cannot establish an environment (science review, 2026-08-30).
Fossils are binned to their nearest slice age by age-range midpoint, with boundaries at the inter-slice midpoints 83, 125, 175 and 225 Ma. Those boundaries are an editorial choice, not a published stratigraphic scheme; a reviewer may prefer stage boundaries. Every occurrence keeps its own age range so the choice can be re-examined.
Sources
Macrostrat — the rock of the regionRead from version 2.3.9 of its data service on 2 September 2026.Peters, S.E. et al. Macrostrat: a platform for geological data integration and deep-time research. https://macrostrat.org, accessed on (date)Palaeogeography: Wright, N., Zahirovic, S., Müller, R. D., and Seton, M. Towards community-driven paleogeographic reconstructions: integrating open-access paleogeographic and paleobiology data with plate tectonics. Biogeosciences 10:1529-1541
The Paleobiology Database — the fossils dug up nearbyPBDB publishes no dataset version string; the data-service path (data1.2) and the datainfo access_time bound this claim.Fossil occurrence data from the Paleobiology Database (https://paleobiodb.org), released under CC0 1.0.Palaeo-coordinate cross-check (Paleobiology Database `pgm=gplates`): Wright et. al., 2013; Towards community-driven paleogeographic reconstructions.Palaeo-coordinate cross-check (Paleobiology Database `pgm=scotese`): Scotese, C.R., 2021. An Atlas of Paleogeographic Maps: The Seas Come In and the Seas Go Out, Annual Reviews of Earth and Planetary Sciences, v. 49, p. 669-718.Palaeo-coordinate cross-check (Paleobiology Database `pgm=seton`): Seton et. al., 2012; Global continental and ocean basin reconstructions since 200 Ma.
The EarthByte plate model — where this ground used to beMULLER2019 version 3.0, run with pyGPlates 1.0.0, licensed CC BY 4.0.GPlates: Müller, R. D., Cannon, J., Qin, X., Watson, R. J., Gurnis, M., Williams, S., Pfaffelmoser, T., Seton, M., Russell, S. H. J., Zahirovic S. (2018). GPlates: Building a virtual Earth through deep time. Geochemistry, Geophysics, Geosystems, 19, 2243-2261. https://doi.org/10.1029/2018GC007584Reconstructions computed with the GPlates Web Service (EarthByte Group, The University of Sydney).Plate model: Müller, R. D., Zahirovic, S., Williams, S. E., Cannon, J., Seton, M., Bower, D. J., Tetley, M. G., Heine, C., Le Breton, E., Liu, S., Russell, S. H. J., Yang, T., Leonard, J., and Gurnis, M. (2019), A global plate model including lithospheric deformation along major rifts and orogens since the Triassic. Tectonics, vol. 38, https://doi.org/10.1029/2018TC005462. Licensed CC BY 4.0.Plate model: Zahirovic, S., Eleish, A., Doss, S., Pall, J., Cannon, J., Pistone, M., Tetley, M. G., Young, A., & Fox, P. (2022). Subduction kinematics and carbonate platform interactions. Geoscience Data Journal, 9(2), p.371-383. Licensed CC BY 4.0.Coastline and static-polygon data by the EarthByte Group, licensed CC BY 3.0 Unported.
This record was assembled on from the datasets above. The ancient positions are reconstructions from a published plate model, not observations.
