I think it was probably a secret organization in the 22nd century that also had a portal of its own. That would mean that they probably have ran off to the badlands finding a way to survive with recent technology or meds.
- The object found in the Badlands seems to be a wooden ship's figurehead. According to wikipedia, they were mostly put on the front of ships from the 16th to the 19th centuries. The Vikings also used types of figureheads on their ships, but they took the form of stylized monsters like the ones shown here, not realistic depictions of people. And as discussed here and here, sculptures of females were not used as figureheads until the late 18th century, and became popular in the 19th century (as noted by Malcolm Wallace).
- It's unknown how the Phoenix Group knew to look for it in The Badlands. It could be that they (or someone working for their employers, like Lucas Taylor) were able to create another rift that pulled a ship from the 16th-19th century to the world of Terra Nova.
- If another rift exists that was not created by Lucas Taylor or anyone else working for his employers, then a question arises whether this rift is naturally-occurring or was created artificially by some other group with their own technology. In the first case, perhaps these rifts open randomly at different times, and the particle accelerator at Hope Plaza just insured that the one there stayed put. In the second case, it could have been created by an unknown group on 22nd century Earth, but some speculate that it could have been created by a civilization different from our own, even a nonhuman one.
- Some speculate that a rift which pulls a ship through might be associated with the story of the Bermuda Triangle, although there seems to be nothing to suggest this on the show besides the fact that the object found in the Badlands was part of a ship.
- If a whole ship came through, there probably would have been people on it. If the ship arrived a few centuries before Nathaniel Taylor, then since most ships did not carry women, there probably wouldn't be any descendants of the crew around. On the other hand, some ships such as slave ships did have women on board, so it's not impossible there could be surviving descendants of the crew.
- If there are people from the Georgian era living in the Cretaceous, then the people of Terra Nova are not alone. However, this is unlikely, as they not only had no medical supplies with them if they got sick or wounded, but they did not have as much supplies as the people in Terra Nova, nor would they have survived against being eaten by the predators that live near Terra Nova and possibly in the Outlands.