"Backswamps are a common feature of coastal floodplain environments. These are formed when flooded waters become trapped in low-lying areas. Other ponded habitats appear on the floodplain in the form of abandoned tributaries of the meandering rivers. These habitats are common in Hell Creek, and host a variety of flora tolerant to standing water, as these areas are subject to frequent flooding. These plants include colonies of giant cinnamon ferns, which thrive in the bogs, and a host of herbaceous angiosperms (related to modern gingers, hops and cannabis), which grow upon the curved banks of streams."
― Saurian: A Field Guide to Hell Creek
Adult Dakotaraptor jumping in a cypress swamp during the night
Concept art of Hell Creek's cypress swamp, with a subadult Tyrannosaurus looking to a Acheroraptor sitting on a Denversaurus back.
The cypress swamp is a biome characterized by the common presence of large cypress trunks, with wide roots and whitish or brownish bark, that protrude from the water. The cypress swamp is mostly composed by murky freshwater, although, closer to the beach, it may be present on saltwater. This biome is also affected by flooding, which can occur during or after strong rainfall, and this affects every animal that lives in it. This biome is very biodiverse, as it is the main source of water for most of the creatures in the game. Ornithurans and the crocodylomorphs, Borealosuchus and Brachychampsa, can be very commonly found, while the turtle Basilemys may also be found often close to the shore. Lizards, however, are relatively more hard to find in the purely swampy areas, but Chamops and Palaeosaniwa are decently present in the vicinities. Didelphodon can sometimes be seen close to the edge of the water, but prefers the more inland regions. Lepisosteus fish and the choristoderan Champsosaurus are found here and on other riverine and lacustrine freshwater habitats, as they only inhabit freshwater courses and are incapable of going onto land. As for non-avialan dinosaurs, the most commonly found are the Pachycephalosaurus and the ornithomimids, as well as the Thescelosaurus which is most often found around the water. Dakotaraptor, Acheroraptor and Pectinodon can also be found here sometimes. Bigger dinosaurs, like Triceratops, Anatosaurus, Denversaurus and Tyrannosaurus, are sometimes found here, with Anatosaurus and Triceratops being the most common. Triceratops players most commonly spawn around this biome, but usually on slightly elevated terrain, so for their nests to not be flooded by the changing water levels, while still retaining close proximity to the water's edge. This biome is teeming with a wild array of plant life as well. Blechnacean and osmundacean ferns exist, but by far the Equisetum takes the spotlight of one of the most common undergrowth. Cypress trees like the Glyptostrobus and the Taxodium exist in abundance, with the more occasional sequoia trees, like Sequoia and Metasequoia also growing alongside some river banks. Symplocarpus and Zingiberopsis are also very common, in contrast to the less common cannabaceans.
Soil texture for the cypress swamp biome.