REMOVE

1. Orinoco-Essequibo Region
2. Geuda Springs (Kan.)
3. Toiyabe Mountains (Nev.)

WHAT

1. Geology (1)
2. Wall Map (1)

WHERE

1. Great Lakes (1)
2. Northern United States (1)
3. United States (1)

WHO

1. Flint, Richard F. (1)
2. The Geological Society of … (1)

WHEN

1. 1959 (1)