Midwest Ordovician craters: Decorah and Rock Elm

Life in the Ordovician of the Upper Midwest wasn't all warm tropical seas and all the organic particles you could filter. We've already run into giant volcanic eruptions spreading ash far and wide. There was also a significant glaciation at the end of the Ordovician; the ice itself didn't get to tropical North America, but it did lead into major extinctions. We don't have to go to the poles or volcanoes off the coast of North America for dramatic geologic events, though: we only have to go as far as west-central Wisconsin and northeastern Iowa.

The secret identity of "Agathaumas"

If you've been at this dinosaur thing for a while, you've probably encountered this piece of Charles Knight artwork, labeled as Agathaumas:

Agathaumas, Charles Knight's work via Wikimedia Commons.

Titanosaurs in time and space

Nothing too earth-shattering this week, just an adjunct to "Titanosaurs all the way down" featuring these lovingly crafted charts of titanosaur distribution taken from The Compact Thescelosaurus (so you know all mistakes are mine). Given 101 described species to work with, I split the titanosaurs between South America and all of the other landmasses. As with other charts, you'll need to click to embiggen.