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.
Wilma and Fred have nothing up on these accommodations. This is a small dry cave up on our ranch. There are quite a few overhang shelters in the extended “area” I’m familiar with. This is BIG country to say the least. I’ve been up here actively exploring for 20 years. I just found this shelter last year. It’s cozy in there but it’s dry. How many of you would crawl backwards into a dark small cave. I figured I’d see what lived in there lolol.
Hell Creek/Lance formation covers our Ranch. It’s the famous dinosaur fossil bearing sandstone. There are no fossils obvious in this spot. The ridge upon which this shelter is located is typical. Aa hard well “indurated” (google word of the day) sandstone caps it like an umbrella. . The material that washed away to expose this cave was softer/less resistant to erosion. The cap rock usually protects everything under from exposure thus begins the removal of softer rocks surrounding. Eventually you have a hill or a flat topped butte. In this cave, you have a rare case where the cap rock couldn’t keep agents of erosion from removing the loosely consolidated sandstone that obviously used to fill this hole.
Of course here as everywhere agent of erosion like Wind/Water/Ice/Hot/Cold/Rain/Freezing/Thawing are the driving factors to remove boulders by making sand out of them. The sand blows or washes away. This ground used to be covered by thousands of feet of younger sediment. This sediment has been removed by the agents of erosion over the eons leaving this cave. view
Perspective is indeed Everything. #3 Rock Shelter and similar images are done with a REALLY wide angle close focus lens. It’s a little tricky to do at times but properly framed, these winter images are simple subjects with spectacular perspective. (January 2019)
It is snowing here at the Bliss Dinosaur Ranch this morning. We have at least 1/2 an inch on the ground and it’s still coming down hard here pre-dawn. It’s still early….But deep in the winter when I can’t get around so easily in the backcountry, I literally have to plow a couple of miles of two track road to get up on this ridge.
Stay tuned for more of these being “refinished to my current standards. My posts will be mix and match for the next few months to populate the new gallery we’re building with my portfolio. Only 5K more images to go…. 🤣
Happy Oct 1…. Holy cow where did the summer go… ?. 🙂 Be safe out there. New post every 3 hours.
I Found this small natural , a cave with a view as it were…. on my place a few years ago. I don’t get a chance to crawl do deeply into it much though. I just be loosing weight :). It is a favorite haunt of rabbits, snake and other critters trying to keep hidden.