At Devil’s Coulee in Alberta, there are dinosaur bones and Western Interior Seaway clamshell fossils — yawn.
What really got me excited, though, were the armored mud balls!
This phenomenon is as intuitive as it is bizarre. After a big rain, a glob of sticky, self-cohesive mud gets weathered out of the badlands. The globule goes tumbling down hill, where it encounters pebbles. The pebbles (and strands of grass, and grasshoppers, I suppose) stick to (and are partially mashed into) the exterior of the mud ball.
Eventually, it can attain a nice layer of exterior “armor” like an Ankylosaur. Here’s a different view (rotated a bit in perspective, and zoomed in) on that same armored mudball… Note the mudcracks!
A parting shot: two for one!
This was my first time seeing real live armored mud balls in the field. It was a thrill and a half!
Crikey! Talk about ships passing in the night: I was working about 15 minutes away from Devil’s Coulee the entire month of June! My colleague and I visited the coulee on June 16. I don’t recall seeing any armoured mud balls; mind you, I wasn’t particularly looking for them, either! I was impressed enough by all the dino egg shell fragments all over the place.
We were there on the 9th. A week apart!