REMOVE

1. trees
2. tools
3. sky
4. soil
5. hats
6. freight cars

WHAT

1. banks (landforms) (1)
2. black-and-white film (1)
3. bushes (1)
4. erosion (1)
5. fields (land) (1)
6. landscapes (representatio … (1)
7. plants (1)
8. roads (1)
9. rock (1)
10. Visual Works (hierarchy n … (1)
11. woods (plant communities) (1)

WHO

1. Campbell, Sandra L. Still (1)
2. Sandra L. Still Campbell; … (1)

WHEN

1. 1961 (1)
2. after 1961 (1)