I say hi. I also say quite a wealth of words about a place in the Western half of the US called the Morrison formation, which is also half-Canadian.
That’s right, another dinosaurs post.
I know I have gone on record to say that life was most diverse in the Early Cretaceous globally, but in the Morrison in particular the Late Jurassic was the heyday of animal diversity.
Now what US states are in the Morrison? Well, here is the list:
- North Dakota
- South Dakota
- New Mexico
Oh, and the western panhandle of Oklahoma state and the northern panhandle of Texas state are parts of those states that are also in the Morrison formation.
This formation is a sequence of Late Jurassic sedimentary rock that is the most abundant source of dinosaur fossils in the hemisphere if not in the planet. The total size of this mostly-American formation is 600,000 square miles. Formation accessibility tells us that only a tiny fraction of this behemoth dinosaur diversity factory has been unearthed. Think of it, the biggest animal biodiversity on Earth is in this formation and 75% of this biodiversity has yet to be unearthed! Other evidence tells us that much of the western edges of it are gone because of erosion.
This formation, and its Cretaceous equal, the “Hell Creek formation”, are the world’s two most abundant sources of the remains of all the best-known dinosaurs and all the best-known other prehistoric animals to. For example, fossils of the world’s first amphibians are most common in this country’s geologic dig sites.
- Allosaurus and Tyrannosaurus, whose only size differences on each other are a 10,000 pound weight difference (Allosaurus being 5,000 pounds vs Tyrannosaurus at 15,000), a 1-foot neck difference (Allosaurus’s neck at 3 feet vs Tyrannosaurus at 2) and a 2-foot head length difference (Tyrannosaurus with 5 foot head vs Allosaurus’s 3 foot head); were both animals of the Western United States millions of years before a “the United States” even existed.
- Some of the world’s best-protected dinosaurs; Ankylosaurus, and Stegosaurus, were unearthed in this gorgeous nation.
I can go on forever about dinosaur digs unique to America and ones this nation shares with Canada, but I think I am going to stop here. Thank you all for your time,