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So, I'm in the process of writing a book series having to do with prehistory and the like, and I'm trying to make everything as accurate to life as I can while still making it an entertaining story. The first book of this series has to do mainly with the roughly 110 million year old coastal floodplains and hills of Oklahoma/ Northern Texas area, and, while I feel that my dinosaurs are about as accurate as I can make them at this point (Fully feathered Deinonychus, Supinated vs pronated hands in Acrocanthosaurus and Deinonychus, etc.), I need a bit of help with their environment. Thus far, I haven't been able to find hardly anything about the climate, botany, or even a lot of the geography of the area thus far beyond the most simple stuff like lack of grass and warm and humid climate. Now, given that I want to stay as accurate as I can and do every time era justice, I'm not sure where to go from here. Would anyone happen to know or be able to direct me to some of the specifics? As of right now, I'm using a mix of the forests of Eureka, California and parts of New Zealand as my main models, with a hint of southern Florida thrown in as well. Thanks for taking the time to answer this!

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  • $\begingroup$ Err... Tried typing "cretaceous continent map" into a search engine? Lots of results, for instance this: scotese.com $\endgroup$ – jamesqf May 4 '16 at 5:23
  • $\begingroup$ You may want to check out our sister site Earth Science as well. $\endgroup$ – a CVn May 5 '16 at 18:52
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The book Lone Star Dinosaurs is primarily about the dinosaurs themselves, but looking at the preview on amazon it seems to have a fair amount of discussion of what the region was like during the Cretaceous, and mentions various specific formations you could google if the fossils there are from around the right time period.

For botany, I found this page which has a quick summary about plant life:

The terrestrial environments in which Early Cretaceous animals lived were still dominated by ferns, seed ferns, Bennettitaleans, conifers, and cycads, but angiosperms (flowering plants) also became part of the flora at this time, about 135 million years ago. Angiosperms diversified rapidly, and by the end of the Cretaceous were by far the most diverse group of terrestrial plants. Many explanations have been offered for their rapid diversification, but the true explanation is probably quite complex. Some Cretaceous flowering plants may have had their seeds dispersed by animals, but that was also true of other kinds of plants. Today, some species of flowering plants grow rapidly compared with living conifers and cycads, so perhaps the success of their Cretaceous ancestors was related to their rapid growth. Another explanation is that many angiosperms are pollinated by insects; insect pollination is thought to increase the rate at which new species evolve. However, several other groups of Cretaceous plants were also insect-pollinated. Whatever the reasons for the success of the angiosperms, many new groups of insects evolved during the Cretaceous, including the oldest known ants and bees as well as newly evolved groups of pollinating species such as flies, beetles, wasps, and moths. Some paleontologists think that the coincident evolution of these insect groups and the diversification of flowering plants is an example of the process of coevolution, in which two different types of organisms (such as an insect and plant) become specifically adapted to one another. Insects also evolved more types of feeding behavior both in quiet-water habitats such as lakes and in flowing-water habitats.

Googling some of those plant names along with "Cretaceous", I found An Introduction to Mesozoic Palaeobotany which has a map of different plant types in the Cretaceous. There seems to be some detailed discussion of Cretaceous flora starting on p. 319 of Fundamentals of Palaeobotany, some of which is available on google books here. Plants in Mesozoic Time also looks like it could be good (though perhaps more technical than you need) if you want to pick up a book on the subject, and you can click the cover on the amazon page to see some preview pages. Paleobotany: The Biology and Evolution of Fossil Plants looks very comprehensive and has a lot of photos and illustrations, hard copies are expensive but you could rent the kindle edition. Another detailed one dealing with a fossil formation that's fairly close to the time (a little over 90 million years ago) and area (Northeast Arizona) that you wanted is Paleontology of the Greenhorn Cylcothem, previewable on google books here. For a less scientifically-oriented guide with more illustrations, maybe something like Common Fossil Plants of Western North America or Mesozoic Fossils II: The Cretaceous Period or A Field Guide to Fossils of Texas would be helpful.

I also found that this page about a Colorado coastal area from 100 mya, again close to the time and place you're interested in:

enter image description here

Description: Along the shore of a wide, salty sea, low tide has exposed a broad-rippled sandy surface. Mighty rivers flowing from mountains far to the west bring sand and gravel down to the coast. Along the shoreline is a dank coastal forest containing herbaceous ferns (Astralopteris and Matonidium), broad-leaved trees (Sapindopsis, Liriophyllym, and Protophyllum) and strange conifers. A few Iguanodon dinosaurs wander down the beach, leaving their footprints on the rippled surface.

Googling one of the plants named (Matonoidium) along with "Colorado" and "Albian" (since 110 million years ago would have been during the Albian age which lasted from 113-100 mya) turned up this very detailed paper on the spread of angiosperms in the Cretaceous (flowering plants whose sex cells are enclosed in ovaries like fruits or hard seeds, including most of the non-pine trees you see in modern forests like oaks, maples, palm trees etc., as opposed to gymnosperms like conifers and cycads, or ferns which are neither angiosperms nor gymnosperms), which has a section on "Texas and adjacent states" on p. 236. It notes that "Angiosperms may not have penetrated the Gulf Coast region by the time of the Aptian-Albian boundary" (i.e. the beginning of the Albian 113 million years ago), but angiosperm pollen begins to be found from the Early to Middle Albian and leaf remains are found in the Middle Albian (I also found a chart on p. 193 of The Evolution of Plants showing angiosperm leaf and pollen types in the Albian, although the description says it's from "Eastern North America" where angiosperms started taking over a little earlier...the chart does show the time ranges of the early, middle, and late Albian, suggesting that 110 million years ago would still be in the 'early' period). This might suggest that angiosperms would still have been rare in the Texas area 110 million years ago, in which case you should ignore all the "broad-leaved trees" in the above quote. The wikipedia article on angiosperms linked above also notes that they "replaced conifers as the dominant trees during 100 to 60 mya", so assuming that's correct, 110 million years ago you should have mainly coniferous forests--this page has some details about the types of conifers that were most populous during the early Cretaceous, and it includes this chart from a paper the writer uses as a reference:

enter image description here

The second row labeled T2 covers 126-99 million years ago, it looks like during this span the Texas coast area would be expected to feature trees from the families Araucariacaea, Cupressacaea, possibly Pinaceae although the map only seems to show Pinoids slightly further North than the Southern coast; angiosperms are also seen on the right map for T2, but as I said this may be mostly from later parts of the Albian.

Some other googling showed that Paluxy River and the Glen Rose Formation were a source for a lot of Texas fossils from around the Albian period, googling "Glen Rose Formation" along with some plant-related terms like "trees" or "cycads" or "flora" may turn up some useful results, for example I found the paper Paleoenvironment at Jones Ranch, an Early Cretaceous Sauropod Quarry in Texas, U.S.A which says this quarry dates from the "Aptian-Albian boundary" (i.e. around 113 million years ago, very close to the time you want), and p. 84 has a section on "flora and fauna" with a paragraph on plant life:

Fossil plants from the Trinity Group demonstrate that angiosperms were present in the flora of Texas, but not yet abundant (Kessler, 1968; Jacobs, 1989). Ferns, cycads, bennettitaleans, and conifers have been recognized (Fontaine, 1893; Jacobs, 1989). Axsmith and Jacobs (2005) have referred the cones, branches and cuticles found at Jones Ranch to the conifer Frenelopsis ramosissima. Male cones found at the site contain Classopollis-type pollen. This together with the wood anatomy of the petrified logs all support attribution of Frenelopsis ramosissima to the family of extinct conifers Cheirolepidiaceae. Thus, the vast majority of the abundant plant remains at Jones Ranch, and all that are identifiable, can be referred to a single conifer species. Previous work on the paleoecology of Frenelopsis and Pseudofrenelopsis (both members of the family Cheirolepidiaceae and known from Early Cretaceous deposits in the eastern U.S. and England) has suggested that many species bore adaptations for water stressed (xeric) or halophytic environments (Upchurch and Doyle, 1981). It is common for members of this family to occur in low diversity assemblages (Gomez et al., 2001). Upchurch and Doyle (1981) however, noted that in the eastern U.S., Frenelopsis ramosissima occurs in a diverse mesic assemblage. Others had reconstructed this species as a small shrub (Axsmith and Jacobs, 2005). Evidence from Jones Ranch now supports the interpretation of Frenelopsis ramosissima as a large tree reaching over 20 m in height and living in low diversity or monospecific stands under a semi-arid climate near the coast (Axsmith and Jacobs, 2005). The sauropod dinosaurs found at Jones Ranch inhabited a coastal region dominated by ferns, multiple conifers, cycads, and cycadeoids, but they also dwelt in low diversity conifer forests inland.

For a visual reference on the type of tree they describe above as most common in the region, here is a paleoartist's rendition of a dinosaur with some Frenelopsis ramosissima trees in the background (click to enlarge):

enter image description here

And searching for more on Frenelopsis ramosissima and "Albian", I found page 40 of Biology of the Sauropod Dinosaurs which says:

it is interesting to note that Early Cretaceous cheirolepidiaceans occur in coastal sediments in Texas in which sauropod trackways and bonebeds have been discovered. One species (Frenelopsis varians) was collected from the Glen Rose Formation at a site northwest of Austin, Texas, and grew in low colonies in salt marshes near a hypersaline lagoon or bay depositional system (Daghlian & Person 1977). A second species of Frenelopsis, F. ramosissima, was found in a sauropod bonebed in the Twin Mountains Formation on the Jones Ranch southwest of Fort Worth and, in contrast, formed a monospecific stand of massive trees in a semiarid coastal forest (Axsmith & Jacobs 2005).

The paper by Axsmith & Jacobs referenced above is available online here, p. 2 notes "The Twin Mountains Formation at the level of the Jones Ranch site is approximately equivalent to the lower part of the Glen Rose Formation and is most likely between 110 and 112 Ma", so right at the time and place you wanted to write about. And p. 336 says:

the Texas assemblage appears to represent a monospecific stand of F. ramosissima ... Further, sedimentological features at Jones Ranch ... indicate a semiarid climate (Winkler et al. 2000). This climatic interpretation, along with the fact that the coastline of the Texas platform sea was just a few kilometers from the Jones Ranch site during the time of deposition, indicates that F. romosissima could closely approximate one of the classic paleoecological interpretations of the frenelopsids as arid coastal forest-inhabiting xerophytes

As for geography, I searched for "Cretaceous Albian North America" and found this powerpoint presentation which features this map (click to enlarge) that says it depicts North America during the period 108-100 mya:

enter image description here

The map appears to come from this site, probably from this DVD which has 60 maps of the Western Interior Seaway at different times.

Searching "Albian Cretaceous North America paleoclimate" turned up this paper which includes a map of the reconstructed global vegetation distribution in the early Albian, see map (b) in Fig. 6 on p. 655. The map isn't very high-resolution but it seems to indicate the area just north of the ocean boundaries in the previous map would have been in either the "closed canopy, broad leaved, dry deciduous forest" category or the "closed canopy, broad leaved, moist evergreen forest", depending on how far west you want the characters to be.

I also found that the book Jurassic and Cretaceous Floras and Climates of the Earth has a detailed discussion of plant life in the "western states of the USA" during the Albian age, starting on p. 137 which is viewable on google books here. And p. 140 discusses the climate:

Passing on to the estimation of the USA climate in the Early Cretaceous epoch it is necessary to pay attention to the rarity of plant discoveries in the Neocomian as well as to their increased number in the Albian. This is likely to be associated with increased humidity of climate toward the end of the Early Cretaceous. In pre-Albian time (at least in the southern part of the USA) the climate was dry which is signalled by the finds of Cheirolepidiaceae in Colorado (Aptian) and Texas (Glen Rose suite).

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As far as temperature was concerned the climate throughout the USA during the Early Cretaceous epoch was subtropical, as is supported by the extensive dissemination of the barrel-shaped trunks of Cycadeoidea.

This seems to conflict a little with the earlier description from Axsmith & Jacobs of the Texas coastal area as "semiarid", but maybe when that quote says "In pre-Albian time (at least in the southern part of the USA) the climate was dry", this should be extended to the earliest part of the Albian (including about 110 million years ago) as well.

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  • $\begingroup$ This is extremely helpful! I'm going to leave this open for other answers for a bit longer in case anyone else has anything to add, but you have no idea how much this helps me. Thanks so much! $\endgroup$ – TheTimeVoyager May 5 '16 at 0:03
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    $\begingroup$ Great answer. Not only for the information itself, but also for showing how you put it together. $\endgroup$ – Tonny May 5 '16 at 7:41

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