| 21. | Oak, blackgum, tulip and yellow birch trees are common in the woods that cover the valley walls.
|
| 22. | The strata exposed in the valley walls provide an important and easily accessible record of Etna's eruptive history.
|
| 23. | Across the park from this site there are several shallow caves carved by springs in the valley wall.
|
| 24. | He took water samples from rivers and from higher up on the valley walls at faults and springs.
|
| 25. | Landslides are very common along the river bank as cliff-like bedrocks are significantly exposed along the river valley wall.
|
| 26. | These constitute the valley walls of the Great Valley, which runs generally west to east toward the Schuylkill River.
|
| 27. | The process of erosion carved away the ancient valley walls leaving the lava flows rising above the surrounding terrains.
|
| 28. | Within Organ Pipes National Park, the valley walls of Jacksons Creek expose Pleistocene volcanic rocks of the New Volcanic Group.
|
| 29. | The stream's valley walls and the area surrounding the valley has surficial geology featuring bedrock consisting of sandstone and shale.
|
| 30. | The scarring caused by the avalanche was increasingly higher above the stream bed on the creek valley walls nearer the reservoir.
|
