REMOVE

1. hills
2. railroads
3. rock
4. water tanks

WHAT

1. banks (landforms) (1)
2. black-and-white film (1)
3. bushes (1)
4. freight cars (1)
5. landscapes (representatio … (1)
6. sheds (storage structures … (1)
7. soil (1)
8. trains (vehicle groupings … (1)
9. trees (1)
10. utility poles (1)
11. Visual Works (hierarchy n … (1)

WHO

1. Clyfford Still; Still, Cl … (1)
2. Still, Clyfford (1)

WHEN

1. 1920 (1)
2. 1940 (1)
3. between 1920 - 1940 (1)