Related Clues:

• Four-footed moms
• Roosevelt and Hoover
• Muscles
• River structures
• Gas and gasohol
• Fills the tank
• Gas, wood, coal, etc.
• Some four-footed mothers
• Obstructs
• Wood and coal, e.g.
• Emulates beavers
• Blocks up
• Firefighters
• Beavers' creations
• Iron-pumpers' displays