News and views from the geologic realm
#1: Boxwork type veins (from a concretion?)#2: Tool marks (trace fossil on a sandy(?) substrate.
Upper one look like inverted cast of mudcracks- sand infills cracks, and after lithifcation, withstands weathering better than underlying mudstone. Lower one less certain about, but looks like some kind of drag marks. Amphibian/reptile tail(s)?
First one is cast of dino footprint in mudcracked mud, with the cracks radiating out from the footprint like a spider web, indicating the footprint came first or contemporaneously with the stresses that caused the mud to crack. Not sure about the second one...
The first is inverted mudcracks. The second are swimming tracks from a dinosaur.
I agree with Ron Schott...
Top one looks like "worm burrows" in the Kaibab Limestone.
1. I agree with Callan, I didn't notice the footprint until he pointed that out.2. Trace fossil? Maybe feeding traces (like from a trilobite?)
I have to say I really don't know, but these photographs are MOST delightful to contemplate. Imagination (esp. since I am a geology ignoramus) is a fun muscle to exercise. That 1st one (ignoring all the erudite guesses your blog visitors have posted) is a TOTAL mind bender!The 2nd looks a bit like BIG ol' leaves, but guessing from above comments, not likely. =)
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