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You Have to be Swift

You Have to be Swift
You Have to be Swift

You Have to be Swift

Well a “White Throated Swift” if I read my audubon ID correctly. They are silly fast birds. Getting one launching from it’s home…. lol. My reaction time isn’t as fast as in my youth. As a geologists I’m less interested in the bird instead of the WONDERFUL geology behind it. I’m always thinking about Cretaceous river systems operating up here in the rock record. Geologists read rocks like a book. The local rocks make for a great story ! ..

Transition to geology:

Indeed this Swift is a cliff dweller exiting that dark subsoil homestead built out of the Cretaceous Hell Creek/Lance formation Cretaceous River bottom sediment exposed here. Those various “rocks” are all different kinds of mudstone “pebbles”. These were rolled down a very large paleo-river. Each rock torn up from the clay river bottom up stream then rounded along the way. There is a nice mix of clast sizes represented in the wall. The current velocity in that paleo-river obviously carried these pebbles to cobble sizes down river only to dump them here at this spot. That river lost it’s ability to carry this material leaving it behind for me to observe 66 million years later. No fossils in this debris which represents the source’s likely-hood of having bones in the clay. (way long discussion ommitted).

Somewhat more recently, rain water has very carefully washed the sand away from the pebbles showing this well exposed “cobblestone surface that is resultant from that pre-historic river depositional event. Notice I didn’t say “flood”. Floods wash sediment down stream as well as scouring clay chunks out of the floor of the stream. It’s the cessation of that flood that leaves this kind of debris as these transported mud clasts behind. Slower velocity drops the suspended and saltated load instantly. This pile of river gravel was eventually covered by another river cycle of deposition. The next depositional event overlapping rinse and repeat millions of times. The same river swept back and forth across the Cretaceous piedmont filling the epi-continenal sea at the time. Dinosaurs skinny dipped in these rivers sands/cobbles.

Location: Bliss Dinosaur Ranch, Wyoming/Montana borderlands (Wyotana)

Title: You Have to be Swift

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Dinosaur Horns Assortment

Dinosaur Horns Assortment
Dinosaur Horns Assortment

Dinosaur Horns Assortment

These are nose horns from various Triceratops with perhaps a dermal scute from Ankylosaur in the front row that looks like Apollo 11 re-entry capsule.

Each horn has it’s story regarding how I found it, the “Eureka” moment, the rush of adrenaline. I have only prepped the rear one. As they were found, the remaining stay. Restoration occurred on the BIG horn in the rear. It was in 80 separate pieces when I found it.. Restored to “pretty cool” condition. I’ll post it later. The best one is the smallest on up front row. It’s an amazing fossil.

Paleontological Musings:

Triceratops horns are like cattle horns in that they take on many different shapes even within the same group. These are all from the same bone bed I call “Horn Sieve Beds” as they have given up over 30 of them to me.

Hell Creek/Lance Formations are the Cretaceous River Sands/muds is where the last of the dinosaurs hung out. Both formations cover our ranch. We span the MT/WY state line. There the Formations change names formally. Same rocks, different name.🤣

I got my masters degree around most things Paleo-Environmental……. I might have been one of the first Pale-environmentalist ever minted lolol. There is another that will read this I graduated with. Hi Dave!

So, paleo-topography when this dinosaur roamed was a broad equatorial coastal plain sloping like the piedmont of North Carolina east facing toward the then interior sea way stretching from the current Gulf of Mexico across the continent to Canada.

Location: Bliss Dinosaur Ranch, Wyoming/Montana borderlands (Wyotana)

Title: Dinosaur Horns Assortment

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Triceratops Vertebra with Processes

Triceratops Vertebra with Processes
Triceratops Vertebra with Processes

While finding a Cretaceous age Triceratops Vertebra with Processes still attached is possible, it doesn’t happen very often with an isolated fossil not attached to another bone.

Geologic Musings:

I spent many years working on determining paleo-environments. It the environment of deposition that produced rock deposits. This can be determined from any number of clues left in the rocks. (Wrote a Masters thesis on this). I am biostratigraphically and sedimentologically very aware of how this Triceratops vertebra with processes got to be here…cer. There are many indications to what was going on during it’s deposition. This Bentonitic Clay rich Mud was on the edge of a lake. This deposit consisted of what was then Volcanic Ash as a “dump” was washed into the lake hydraulically. That washed in volcanic “mud” made a “deltaic” intrusion into the much larger lake.

This particular bed of sediment I have traced over about 2 square miles. I loose visual on the bed as it disappears either underground or has been removed by erosion. So this was a pretty big lake and a big delta deposit into that lake. Represented is not a high energy Splay deposit that might exist next to a big natural river levy (highest things on the landscape probably). It’s not high energy like a splay proven from the lack of larger chunks of plant matter….

There were BIG rivers sweeping back then. Sweeping back and forth carrying LOTS of sand during this time in Wyoming/Montana. The sand was mixed along with this finer material (clays) by the boat load and dumping it. Low energy let the fine clays settle out (like in lakes). Otherwise the clays (size term just like sand) would stay in suspension in agitated water. This had to be a calm environment like a lake. Most of my Hell Creek Fossils are found in RIver NOT lake deposits by the way lol.

Considerations:

That volcanic ash was altered over the 66 million intervening years into “Bentonite” which is an incomplete description of the sediment. Bentonite is just ONE Clay mineral that is represented here. Dozens of clay minerals are in this mix. Digging in this stuff is like pushing a wood awl through very thick hard modeling clay. Sometimes you can get it in a few inches, others just a quarter of an inch. You stick and pluck the awl and slowly clear off sediment to facilitate this treasures removal. It’s all very moist and most of the fossils have a white crust around them. They usually clean up beautifully brown.

Overview

Maybe 20 percent of this Triceratops was recovered nearby this isolated Triceratops vertebra with processes. We finally all gave up looking for more of the carcass. It could be 1 inch down and we wouldn’t know it lolol. It’s bones were obviously scattered/fed on and stepped on after it floated into the lake at least once. I noted that ALMOST all the bone fossils in this deposit were laying flat horizontal to the lake bottom. One rib was obviously stepped on as it was broken in half with 1/2 of it being vertical. It was pushed down into the mud by someone walking over. I’ve found coprolites (fossil poop) here too. This would be indicating that active feeding and pooping was happening for a while. Also found a smaller raptor tooth in the mix. (Dromaeosaur richaroestacia. (sic).

The soft organic rich mud covering the fossil was rich in small fragments macerated plant matter. This is an obvious lake deposit covering several square miles at a minimum. The energy was very low here. Calm water, no doubt shallow as the wading dinosaurs confirm. There was not a lot of topography on the Hell Creek Formations mostly sandy river deposits on a broad sweeping plane. Much of a rib cage was recovered along with a scapula and several other very nice fossils from this animal. I found this site by tracing a big chunk of Triceratops Brow Horn back up hill to where it came from. Took a few looks lol.

Location: Bliss DInosaur Ranch, Wyoming/Montana borderlands.

Triceratops Vertebra with Processes