1. Unit 9 – Which Way Up? Sedimentary rocks, Waterton Lakes-Glacier International Peace Park. Colored lines follow a folded layer. Right-side-up at the green line becomes mostly upside-down at yellow, right-side up at orange, and slightly upside-down at red, as shown by the black arrows.

2. Unit 9 – Which Way Up? Dinosaur Ridge, near Denver. Above, a stone surface that was mud when the dinosaurs stomped on it. Our view is quite similar to what the dinosaurs would have seen, looking down on their feet going down in the mud. Right, the red outline shows the footprint of a dinosaur (green coloration of foot being pulled out of mud is purely conjectural!), down into mud (notice that the layers on the far left are broken or bend down at the red line). Later, more mud washed in to fill the footprint, and then everything was hardened to stone. We’ll see more of these prints in unit 11. (Dr. Alley for scale; that was a large dinosaur foot!)

3. Unit 9 – Which Way Up? Part of a fossil sand dune. The picture in the upper-left corner shows the original, right-side-up dune. Wind blew from the right to the left, building a dune layer-by-layer as sand blew over the crest and avalanched down (the magenta arrow shows the sand motion). Then, more erosion occurred (along the green lines), cutting the tops off the layers, and then more sand was deposited above. If you had flopped down on your back and looked at the sky when this was forming, you would have gotten sand in your eyes, but you would have been looking in the direction the blue arrow points--up. You might see the other pictures if nature had flipped the rocks various ways. The blue arrows, which point in the “up” direction in each case, will help you follow the flips, but as an experienced Geosc10 geologist, nature can’t fool you any more. The key is that sand was deposited and then cut by the wind, wind cannot cut sand that isn’t there, so the cut ends are “up”. (There’s a bit more complexity in the far lower right of the original picture, telling of another event, but don’t worry.)

4. Unit 9 – Which Way Up? A cliff below the South Rim of the Grand Canyon, along the Bright Angel Trail. The redder Hermit Shale (below the yellow line) is a flood- plain deposit, and sand from the Coconino Sandstone dunes (above the yellow line) fell into a huge mud crack extending perhaps 20 feet downward (below the red arrow). A sand dune blowing onto the flood plain of the Nile could produce a similar deposit today. This is right-side up; the sand fell down into the mud crack.

5. Unit 9 – Which Way Up? Lava flow, Sunset Crater National Monument, Arizona. Bubbles tend to rise in lava flows, as they do in soda, but to be trapped beneath the quick- cooled upper layer, as would happen if you quick-froze the top of your soda. Often, bubbles will be bigger and more numerous toward the top of a cooled lava flow, as in this one. This flow is right-side-up.

6. Unit 9 – Which Way Up? Mud cracks and Dr. Alley’s index finger, Arches National Park. Mud dried, cracked, a new mud layer was deposited on top, both hardened, layers were split, and the top one turned over for you to see here. This piece of rock is now upside-down. Compare the shadows from Dr. Alley’s finger and the reddish rock ridges to see that these really are ridges and not valleys.

7. Unit 9 – Which Way Up? These mud cracks are from the Flagstaff Limestone of central Utah, very similar in age and setting to the Bryce Limestone. This slab is right-side up. The cracks go down, as you can see by comparing the shadows in the cracks with the shadow from Dr. Alley’s pocket knife.

8. Unit 9 – Which Way Up? Along I-70 in central Utah. The reddish rocks below are sediments from a coastal environment, and the originally horizontal layers are now vertical (look just above the geology student, shown by the black arrow, which also points along the layers). Above the reddish rocks is a reddish fossil soil or paleosol (shown by the blue arrow; notice the horizon of white caliche nodules just below the blue arrow, indicating a rather dry climate when the soil formed). Above the soil are whitish lake sediments. Try telling the story shown here.